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1.
Ultrasound Obstet Gynecol ; 58(4): 590-596, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34090307

RESUMEN

OBJECTIVES: In fetuses with isolated left-sided congenital diaphragmatic hernia (LCDH), prenatal detection of severe pulmonary hypoplasia is important, as fetal therapy can improve survival. Cases with mild or moderate lung hypoplasia still carry a considerable risk of mortality and morbidity, but there has been less interest in the accurate prediction of outcome in these cases. In this study of fetuses with mild or moderate isolated LCDH, we aimed to investigate: (1) the association between intrapulmonary artery (IPA) Doppler findings and mortality at discharge; (2) whether adding IPA Doppler findings improves the prediction of mortality based on lung size and liver herniation; and (3) the association between IPA Doppler findings and early neonatal morbidity. METHODS: This was a retrospective study of all consecutive fetuses assessed at the BCNatal and UZ Leuven hospitals between 2008 and 2020 with a prenatal diagnosis of isolated, non-severe LCDH, defined as observed-to-expected lung-to-head ratio (o/e-LHR) > 25%, that were managed expectantly during pregnancy followed by standardized neonatal management. An additional inclusion criterion was the availability of IPA Doppler measurements. The primary outcome was the association between IPA Doppler findings and mortality at discharge. Other predictors included o/e-LHR, liver herniation and gestational age at birth. Secondary outcomes were the association between IPA Doppler findings and the presence of pulmonary hypertension (PHT), need for supplemental oxygen at discharge and need for extracorporeal membrane oxygenation. IPA pulsatility index (PI) values were converted into Z-scores. Logistic regression analysis was performed to investigate the associations between predictor variables and outcome, and the best model was chosen based on the Nagelkerke R2 . RESULTS: Observations for 70 non-severe LCDH cases were available. Fifty-four (77%) fetuses survived until discharge. On logistic regression analysis, higher IPA-PI was associated with an increased risk of mortality (odds ratio (OR), 3.96 (95% CI, 1.62-9.70)), independently of o/e-LHR (OR, 0.87 (95% CI, 0.79-0.97)). An IPA-PI Z-score cut-off of 1.8 predicted mortality with a detection rate of 69% and specificity of 93%. Adding IPA-PI to o/e-LHR improved significantly the model's performance (Nagelkerke R2 , 46% for o/e-LHR + IPA-PI vs 28% for o/e-LHR (P < 0.002)), with a detection rate of 81% at a 10% false-positive rate. IPA-PI was associated with PHT (OR, 2.20 (95% CI, 1.01-4.59)) and need for oxygen supplementation at discharge (OR, 1.90 (95% CI, 1.10-3.40)), independently of lung size. CONCLUSIONS: In fetuses with mild or moderate LCDH, IPA-PI was associated with mortality and morbidity, independently of lung size. A model combining o/e-LHR with IPA-PI identified up to four in five cases that eventually died, despite being considered to have non-severe pulmonary hypoplasia. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.


Asunto(s)
Enfermedades Fetales/mortalidad , Hernias Diafragmáticas Congénitas/mortalidad , Arteria Pulmonar/diagnóstico por imagen , Ultrasonografía Doppler/estadística & datos numéricos , Ultrasonografía Prenatal/estadística & datos numéricos , Oxigenación por Membrana Extracorpórea/estadística & datos numéricos , Femenino , Enfermedades Fetales/diagnóstico por imagen , Feto/diagnóstico por imagen , Feto/embriología , Feto/patología , Cabeza/diagnóstico por imagen , Cabeza/embriología , Cabeza/patología , Hernias Diafragmáticas Congénitas/diagnóstico por imagen , Hernias Diafragmáticas Congénitas/embriología , Humanos , Hipertensión Pulmonar/congénito , Hipertensión Pulmonar/diagnóstico por imagen , Hipertensión Pulmonar/embriología , Recién Nacido , Modelos Logísticos , Pulmón/diagnóstico por imagen , Pulmón/embriología , Pulmón/patología , Morbilidad , Oportunidad Relativa , Valor Predictivo de las Pruebas , Embarazo , Arteria Pulmonar/embriología , Flujo Pulsátil , Estudios Retrospectivos
2.
Ultrasound Obstet Gynecol ; 57(3): 378-385, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-32924187

RESUMEN

OBJECTIVE: To evaluate the neonatal outcome of fetuses with isolated right-sided congenital diaphragmatic hernia (iRCDH) based on prenatal severity indicators and antenatal management. METHODS: This was a retrospective review of prospectively collected data on consecutive cases diagnosed with iRCDH before 30 weeks' gestation in four fetal therapy centers, between January 2008 and December 2018. Data on prenatal severity assessment, antenatal management and perinatal outcome were retrieved. Univariate and multivariate logistic regression analysis were used to identify predictors of survival at discharge and early neonatal morbidity. RESULTS: Of 265 patients assessed during the study period, we excluded 40 (15%) who underwent termination of pregnancy, two cases of unexplained fetal death, two that were lost to follow-up, one for which antenatal assessment of lung hypoplasia was not available and six cases which were found to have major associated anomalies or syndromes after birth. Of the 214 fetuses with iRCDH included in the neonatal outcome analysis, 86 were managed expectantly during pregnancy and 128 underwent fetal endoscopic tracheal occlusion (FETO) with a balloon. In the expectant-management group, lung size measured by ultrasound or by magnetic resonance imaging was the only independent predictor of survival (observed-to-expected lung-to-head ratio (o/e-LHR) odds ratio (OR), 1.06 (95% CI, 1.02-1.11); P = 0.003). Until now, stratification for severe lung hypoplasia has been based on an o/e-LHR cut-off of 45%. In cases managed expectantly, the survival rate was 15% (4/27) in those with o/e-LHR ≤ 45% and 61% (36/59) for o/e-LHR > 45% (P = 0.001). However, the best o/e-LHR cut-off for the prediction of survival at discharge was 50%, with a sensitivity of 78% and specificity of 72%. In the expectantly managed group, survivors with severe pulmonary hypoplasia stayed longer in the neonatal intensive care unit than did those with mildly hypoplastic lungs. In fetuses with an o/e-LHR ≤ 45% treated with FETO, survival rate was higher than in those with similar lung size managed expectantly (49/120 (41%) vs 4/27 (15%); P = 0.014), despite higher prematurity rates (gestational age at birth: 34.4 ± 2.7 weeks vs 36.8 ± 3.0 weeks; P < 0.0001). In fetuses treated with FETO, gestational age at birth was the only predictor of survival (OR, 1.25 (95% CI, 1.04-1.50); P = 0.02). CONCLUSIONS: Antenatal measurement of lung size can predict survival in iRCDH. In fetuses with severe lung hypoplasia, FETO was associated with a significant increase in survival without an associated increase in neonatal morbidity. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.


Asunto(s)
Oclusión con Balón/estadística & datos numéricos , Fetoscopía/estadística & datos numéricos , Hernias Diafragmáticas Congénitas/diagnóstico por imagen , Hernias Diafragmáticas Congénitas/embriología , Ultrasonografía Prenatal/estadística & datos numéricos , Adulto , Oclusión con Balón/métodos , Femenino , Fetoscopía/métodos , Edad Gestacional , Hernias Diafragmáticas Congénitas/cirugía , Humanos , Recién Nacido , Modelos Logísticos , Pulmón/diagnóstico por imagen , Pulmón/embriología , Imagen por Resonancia Magnética/estadística & datos numéricos , Valor Predictivo de las Pruebas , Embarazo , Resultado del Embarazo/epidemiología , Estudios Prospectivos , Estudios Retrospectivos , Tasa de Supervivencia , Tráquea/embriología , Tráquea/cirugía , Resultado del Tratamiento , Espera Vigilante/estadística & datos numéricos
3.
Cir Pediatr ; 30(2): 89-94, 2017 Apr 20.
Artículo en Español | MEDLINE | ID: mdl-28857531

RESUMEN

OBJECTIVES: In gastroschisis pregnancies, a) to correlate prenatal ultrasound variables with postnatal outcome and b) to determine the ideal time for setting the delivery in order to achieve the best neonatal outcome. MATERIAL AND METHODS: Retrospective review (2000-2015) of all available gastroschisis whose prenatal findings could be correlated with the neonatal outcome. Two study groups have been defined according to the complications present after birth: favorable gastrosquisis and complicated. Prenatal variables were compared by groups using McWhitney or Chi tests as needed. RESULTS: Twenty-two gastroschisis fulfilled the requirement. Twelve cases had uneventful outcomes. Ten patients experienced complications, including death in five. In the complicated group there were 15 episodes of sepsis and 17 reoperations. Any single ultrasound parameter could predict a bad follow up. In thirteen cases, delivery was forced due to sudden changes on ultrasound bowel appearance. Nine of these patients had very good neonatal outcome. CONCLUSIONS: Finishing pregnancy when sudden changes on the fetal bowel were identified was the only strategy that leaded us to diminish the complication rate in gastroschisis.


OBJETIVOS: En las gestaciones con gastrosquisis, a) valorar la presencia de algún dato ecográfico prenatal que pueda predecir la evolución postnatal de la gastrosquisis, y b) determinar el momento ideal del nacimiento de los pacientes con gastrosquisis que se relacione con una mejor evolución postnatal. MATERIAL Y METODOS: Revisión retrospectiva (2000-2015) de las gastrosquisis cuyos datos ecográficos prenatales hemos podido relacionar con las características de los pacientes y su evolución clínica posterior. Se han determinado dos grupos en función de la evolución favorable o complicada de la gastrosquisis. Todas las variables ecográficas prenatales se han comparado entre grupos según los test de McWitney o Chi cuadrado. RESULTADOS: Veintidós gastrosquisis cumplieron el requisito anterior. Doce casos tuvieron una evolución sin incidencias significativas. Diez pacientes tuvieron una evolución complicada, de los cuales cinco fueron exitus. En este grupo hubo 15 episodios de sepsis y 17 reintervenciones. Ningún parámetro ecográfico prenatal predijo con fiabilidad una evolución desfavorable. En 13 casos se finalizó la gestación porque aparecieron cambios súbitos en la ecografía. Nueve de estos pacientes evolucionaron sin ninguna complicación. CONCLUSIONES: Terminar la gestación cuando se produce un cambio súbito de la apariencia ecográfica de los intestinos fetales es la única estrategia que nos ha permitido disminuir la incidencia de complicaciones en los pacientes con gastrosquisis.


Asunto(s)
Enfermedades Fetales/diagnóstico por imagen , Gastrosquisis/diagnóstico por imagen , Resultado del Embarazo , Ultrasonografía Prenatal/métodos , Parto Obstétrico/estadística & datos numéricos , Femenino , Estudios de Seguimiento , Humanos , Recién Nacido , Masculino , Embarazo , Reoperación/estadística & datos numéricos , Estudios Retrospectivos , Sepsis/epidemiología , Factores de Tiempo
4.
Cir Pediatr ; 23(3): 184-8, 2010 Jul.
Artículo en Español | MEDLINE | ID: mdl-23155667

RESUMEN

At the moment the extracorporeal membrane oxygenation (ECMO) constitutes the last link in the therapeutic one of the handling of the respiratory failure in patients with Congenital Diaphragmatic Hernia (HDC). We presented our experience. From January 2001 we arrange the ECMO in neonative UCI. 76 HDC, 13 (3 rights and 10 lefts) they have needed ECMO (one in two occasions; altogether 14 procedures). Criteria of inclusion: refractory hypoxaemia, oxigenaction index > 40 and weight > 2 kg. 5 girls and 8 boys with gestacional age between 35 and 41 weeks (average: 38) and weight when being born between 2,300 and 3,500 grams (average 2,817). In 6 cases (5 transferred from other centers) the diagnosis was posnatal. Of the 7 with prenatal diagnosis, in 4 cases fetal therapy by means of traqueal occlusion had been made. Veno-venous in 8 and veno-arterial procedure in 5. Rank of duration: 68-606 hours, average of 228.35. The surgery has been made before the ECMO in 9 cases, 2 during and 1 later. In an occasion there was no surgery. The complications have been of hemorrágico type in one patient and infectious in three cases with sudden sepsis in one. Precocious mortality has been of 6 patients and delayed the 2 (total 61%). Although this procedure has the high morbi-mortality, it is necessary to consider that is patients very badly prognosis without another alternative (with mortality of the 100%). Multicentric studies are needed to establish indicators prognoses pre and postbirthdays.


Asunto(s)
Oxigenación por Membrana Extracorpórea , Hernias Diafragmáticas Congénitas , Femenino , Hernia Diafragmática/terapia , Humanos , Recién Nacido , Masculino
5.
Arch Soc Esp Oftalmol ; 92(2): 86-92, 2017 Feb.
Artículo en Inglés, Español | MEDLINE | ID: mdl-27236610

RESUMEN

CASE REPORT: The case is presented of a 46-year-old male with right eye proptosis and conjunctival hyperaemia, of 18 months onset. A well-defined intraconal mass was found in the computed tomography. In magnetic resonance this was hypo-intense on T1, enhanced with gadolinium and hyperintense on T2. Excisional biopsy was performed, which was reported as a well-differentiated liposarcoma in the histopathology study. DISCUSSION: Liposarcoma is a malignant adipose tissue tumour. It is very rare in the orbit, with 5 histological types, the most common being myxoid. The treatment of choice is wide surgical excision and may be accompanied with radiotherapy. As it is an infiltrative tumour, It has a high rate of recurrence.


Asunto(s)
Liposarcoma/diagnóstico por imagen , Imagen por Resonancia Magnética , Neoplasias Orbitales/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Biopsia , Terapia Combinada , Medios de Contraste , Evisceración del Ojo , Gadolinio , Humanos , Liposarcoma/patología , Liposarcoma/radioterapia , Liposarcoma/cirugía , Masculino , Persona de Mediana Edad , Neoplasias Orbitales/patología , Neoplasias Orbitales/radioterapia , Neoplasias Orbitales/cirugía , Radioterapia Adyuvante
6.
Arch Soc Esp Oftalmol ; 92(4): 184-188, 2017 Apr.
Artículo en Inglés, Español | MEDLINE | ID: mdl-27132490

RESUMEN

CASE REPORT: A 13-year-old boy presented with right eye proptosis and lateral dystopia. A soft non-pulsatile mass was found in the superomedial orbital region. An excisional biopsy was performed, for which the histopathology reported an epithelioid haemangioendothelioma. DISCUSSION: Haemangioendothelioma is a borderline vascular lesion within the spectrum of clinically benign and malignant tumours. These can arise from soft tissue or bone. There are few reports of these tumours located in the orbit.


Asunto(s)
Hemangioendotelioma Epitelioide , Neoplasias Orbitales , Adolescente , Hemangioendotelioma Epitelioide/diagnóstico , Hemangioendotelioma Epitelioide/cirugía , Humanos , Masculino , Neoplasias Orbitales/diagnóstico , Neoplasias Orbitales/cirugía
7.
Biochim Biophys Acta ; 719(1): 165-7, 1982 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-6756482

RESUMEN

5-Carboxymethyl-2-hydroxymuconic semialdehyde dehydrogenase in the 4-hydroxyphenylacetate meta-cleavage pathway has been purified to 96% homogeneity. The native enzyme, which appears to be a tetramer, has an apparent molecular weight of 210000. The purified enzyme shows a narrow pH optimum at pH 7.8 and does not require ions for its catalytic activity. Under standard assay conditions the enzyme acts preferentially with NAD but reduces NADP at 11% of the rate observed for NAD, primarily because of a difference in Km. Apparent Km values are 6.4 micro M for 5-carboxymethyl-2-hydroxymuconic semialdehyde and 52.2 micro M for NAD.


Asunto(s)
Aldehído Oxidorreductasas/metabolismo , Escherichia coli/enzimología , Fenilacetatos/metabolismo , Cinética , Peso Molecular , NAD/metabolismo , NADP/metabolismo
8.
Biochim Biophys Acta ; 967(3): 354-63, 1988 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-3196755

RESUMEN

The kinetic mechanism of the reaction catalyzed by glucose-6-phosphate dehydrogenase (EC 1.1.1.49) from Dicentrarchus labrax liver was examined using initial velocity studies, NADPH and glucosamine 6-phosphate inhibition and alternate coenzyme experiments. The results are consistent with a steady-state ordered sequential mechanism in which NADP+ binds first to the enzyme and NADPH is released last. Replots of NADPH inhibition show an uncommon parabolic pattern for this enzyme that has not been previously described. A kinetic model is proposed in agreement with our kinetic results and with previously published structural studies (Bautista et al. (1988) Biochem. Soc. Trans. 16, 903-904). The kinetic mechanism presented provides a possible explanation for the regulation of the enzyme by the [NADPH]/[NADP+] ratio.


Asunto(s)
Glucosafosfato Deshidrogenasa/metabolismo , Hígado/enzimología , NADP/farmacología , Animales , Lubina , Cromatografía en Gel , Cromatografía por Intercambio Iónico , Glucosafosfato Deshidrogenasa/antagonistas & inhibidores , Glucosafosfato Deshidrogenasa/aislamiento & purificación , Cinética , Matemática , Oxidación-Reducción
9.
Biochim Biophys Acta ; 953(3): 249-57, 1988 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-3355840

RESUMEN

Two forms of succinic-semialdehyde dehydrogenase have been isolated in Pseudomonas putida. The two enzymes could be separated by filtration on Sephacryl S-300 and their apparent molecular weights were approx. 200,000 and 100,000. The smaller enzyme, which is induced by growth on 4-hydroxyphenylacetate, has been purified to 88% homogeneity by anion-exchange and affinity chromatography. Electrophoresis in sodium dodecyl sulphate gave rise to a molecular weight of 53,000, indicating that the native enzyme is dimeric. Under standard assay conditions this enzyme acts preferentially with NAD but reduces NADP at 9% of the rate observed for NAD. The large enzyme, which is dependent on NADP, is induced by growth on putrescine and its induction is highly coordinated with putrescine: 2-oxoglutarate transaminase, gamma-amino-butyraldehyde dehydrogenase and gamma-aminobutyrate: 2-oxoglutarate transaminase activities. Activity and stability conditions and true Km values for substrate and cosubstrates of the two enzymes were determined.


Asunto(s)
Hidroxibutirato Deshidrogenasa/metabolismo , Pseudomonas/enzimología , Cationes Bivalentes , Cromatografía en Gel , Electroforesis en Gel de Poliacrilamida , Hidroxibutirato Deshidrogenasa/antagonistas & inhibidores , Hidroxibutirato Deshidrogenasa/aislamiento & purificación , Cinética , Peso Molecular , NAD/farmacología , NADP/farmacología , Putrescina/metabolismo , Temperatura , Ácido gamma-Aminobutírico/análogos & derivados , Ácido gamma-Aminobutírico/metabolismo
10.
Biochim Biophys Acta ; 990(3): 225-31, 1989 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-2647149

RESUMEN

Two forms of succinic semialdehyde dehydrogenase have been isolated in Klebsiella pneumoniae M5a1. The two enzymes could be separated by filtration on Sephacryl S-300 and their apparent molecular weights were approx. 275,000 and 300,000. The large enzyme is specific for NADP. The smaller enzyme, which is induced by growth on 3-hydroxyphenylacetic acid, 4-hydroxyphenylacetic acid, 3,4-dihydroxyphenylacetic acid and gamma-aminobutyrate, has been purified to 96% homogeneity by affinity chromatography. The NAD-linked succinic semialdehyde dehydrogenase was able to use NADP as cofactor. Its induction is coordinated with 3- and 4-hydroxylase, the enzymes which initiate degradation of 3- and 4-hydroxyphenylacetic acid. The NAD-linked form is also induced by exogenous succinic semialdehyde. The large enzyme is specific for NADP and has been isolated from a defective mutant which lacked the activity of the NAD-linked succinic semialdehyde dehydrogenase. Activity and stability conditions and true K m values for substrates and cosubstrates of the two enzymes were determined. Some aspects of the induction of the NAD-linked enzyme participating in the metabolism of 4-hydroxyphenylacetic and gamma-aminobutyrate were studied.


Asunto(s)
Hidroxibutirato Deshidrogenasa/aislamiento & purificación , Klebsiella pneumoniae/enzimología , Inducción Enzimática , Hidroxibutirato Deshidrogenasa/metabolismo , Cinética , NAD , NADP
11.
Biochim Biophys Acta ; 880(2-3): 242-4, 1986 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-3510672

RESUMEN

Escherichia coli mutants able to grow in putrescine have been isolated from gamma-aminobutyrate mutants. These mutants show putrescine-alpha-ketoglutarate transaminase and gamma-aminobutyraldehyde dehydrogenase activities. Both enzymes have been characterized, the first of them showing an apparent Km for putrescine of 22.5 microM and the second an apparent Km of 37 microM for NAD and 18 microM for delta-1-pyrroline; the optimum pH values were 7.2 and 5.4, respectively, for the two enzymes.


Asunto(s)
Escherichia coli/metabolismo , Putrescina/metabolismo , Aldehído Oxidorreductasas/metabolismo , Escherichia coli/enzimología , Escherichia coli/genética , Mutación , Transaminasas/metabolismo
12.
FEBS Lett ; 162(2): 420-2, 1983 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-6354749

RESUMEN

A strain of Escherichia coli K-12 defective in pyruvate kinase F has been produced. The existence of this mutant, in conjunction with earlier results, strongly suggests that the two pyruvate kinases in this bacterium are distinct forms and not interconvertible. Either form of pyruvate kinase appeared to be equally effective in the glycolytic conversion of phosphoenolpyruvate to pyruvate. Genes specifying pyruvate kinase A and pyruvate kinase F were present on the small F-prime F506 and the locus for pyruvate kinase F was found to be at minute 36.5 on the E. coli genetic map.


Asunto(s)
Escherichia coli/enzimología , Piruvato Quinasa/genética , Mapeo Cromosómico , Escherichia coli/genética , Mutación , Transducción Genética
13.
Biochimie ; 70(6): 757-68, 1988 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2844305

RESUMEN

Salmonella typhimurium LT-2 can utilize propionate as its sole carbon source. Studies on growth, oxidation by resting cell suspensions and by permeabilized cells, suggest that the propionate is transported by the acetate system. This result was confirmed using labeled propionate and acetate. ATP-monocarboxylate phosphotransferase, acyl-CoA orthophosphate acyl-transferase, propionyl-CoA dehydrogenase, acrylyl-CoA hydratase, lactate dehydrogenase, phosphoenolpyruvate (PEP) synthase and PEP-carboxylase activities have been identified in extracts of cells grown on propionate. Mutants deficient in PEP-carboxylase and synthase are unable to utilize propionate. On the basis of results obtained, it seems that the propionate degradation pathway occurs via acrylate and that PEP-synthase and PEP-carboxylase are essential enzymes.


Asunto(s)
Fosfotransferasas (Aceptores Pareados) , Propionatos/metabolismo , Salmonella typhimurium/metabolismo , Acetatos/metabolismo , Acrilatos/metabolismo , Medios de Cultivo , Glutaratos/metabolismo , Glioxilatos/metabolismo , Isocitratoliasa/metabolismo , Mutación , Oxidación-Reducción , Consumo de Oxígeno , Fosfoenolpiruvato Carboxilasa/metabolismo , Fosfotransferasas/metabolismo , Salmonella typhimurium/crecimiento & desarrollo
14.
Biochimie ; 68(5): 731-7, 1986 May.
Artículo en Inglés | MEDLINE | ID: mdl-3089331

RESUMEN

Kinetic properties of purified 5-carboxymethyl-2-hydroxymuconate semialdehyde (CHMSA) dehydrogenase (EC 1.2.1.-) in the 4-hydroxyphenylacetate meta-cleavage pathway from Escherichia coli have been studied. The temperature--activity relationship for the enzyme from 27 to 45 degrees C showed an Arrhenius plot with an inflexion at 36 degrees C. When 5-carboxymethyl-2-hydroxymuconic semialdehyde and NAD were used as variable substrates, the double reciprocal plots were all linear and the lines intersected at one point below the horizontal axis, suggesting that a sequential mechanism is operating. From the replots of intercepts and slopes against reciprocal substrate concentrations were calculated Km (CHMSA) = 9.0 +/- 1.02 microM, Km (NAD) = 29.1 +/- 4.65 microM and the value for the dissociation constant of enzyme--NAD complex = 6.3 +/- 1.21 microM. ATP and the product of the reaction (NADH) acted as competitive inhibitors of the enzyme with respect to NAD. Apparent Ki values, estimated from Dixon plots, were 25.0 +/- 3.5 and 88.0 +/- 22.1 microM for NADH and ATP, respectively.


Asunto(s)
Aldehído Oxidorreductasas/metabolismo , Escherichia coli/enzimología , Adenosina Trifosfato/farmacología , Aldehído Oxidorreductasas/antagonistas & inhibidores , Aldehídos/metabolismo , Concentración de Iones de Hidrógeno , Cinética , NAD/metabolismo , NAD/farmacología , Temperatura
15.
Biochimie ; 69(11-12): 1161-8, 1987.
Artículo en Inglés | MEDLINE | ID: mdl-3129020

RESUMEN

gamma-Aminobutyraldehyde dehydrogenase from Escherichia coli K-12 has been purified and characterized from cell mutants able to grow in putrescine as the sole carbon and nitrogen source. The enzyme has an Mr of 195,000 +/- 10,000 in its dimeric form with an Mr of 95,000 +/- 1,000 for each subunit, a pH optimum at 5.4 in sodium citrate buffer, and does not require bivalent cations for its activity. Km values are 31.3 +/- 6.8 microM and 53.8 +/- 7.4 microM for delta-1-pyrroline and NAD+, respectively. An inhibitory capacity for NADH is also shown using the purified enzyme.


Asunto(s)
Aldehído Oxidorreductasas/metabolismo , Escherichia coli/enzimología , Aldehído Oxidorreductasas/aislamiento & purificación , Cinética , Sustancias Macromoleculares , Peso Molecular , Termodinámica
16.
Biochimie ; 65(11-12): 629-35, 1983.
Artículo en Inglés | MEDLINE | ID: mdl-6673742

RESUMEN

Malate enzyme (L-malate: NADP+ oxidoreductase (oxalacetate-decarboxylating, EC 1.1.1.40)) has been purified from Pseudomonas putida to 99 per cent homogeneity by heat, ammonium suphate fractionation, gel filtration and anion exchange chromatography. Sodium dodecylsulphate-(SDS)-polyacrylamide disc gel electrophoresis analysis showed an approximate tetrameric subunit with a molecular weight of 52,000. The purified enzyme showed a pH optimum between 8.0 and 8.5 (for Tris-HCl buffer) and required bivalent cations for catalysis; monovalent ions like K+ and NH4+ acted as very effective activators. The temperature-activity relationship for the malate enzyme from 35-80 degrees C showed broken Arrhenius plots with an inflexion at 65 degrees C. The enzyme halflife was 30s at 85 degrees C. The enzyme showed hyperbolic kinetics for both substrates with apparent Km values of 4.0 X 10(-4) M and 2.3 X 10(-5) M for L-malate and NADP+ respectively. From the study of the effects of some compounds on the enzyme, the physiological significance of those produced by fumarate, succinate and oxalacetate can be emphasized.


Asunto(s)
Malato Deshidrogenasa/metabolismo , Pseudomonas/enzimología , Cationes Bivalentes , Estabilidad de Medicamentos , Calor , Concentración de Iones de Hidrógeno , Cinética , Sustancias Macromoleculares , Malato Deshidrogenasa/aislamiento & purificación , Peso Molecular
17.
Biotechniques ; 16(2): 270-2, 274-6, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8179892

RESUMEN

We have designed a new method for high resolution electrophoretic separation of proteins that have similar molecular weights. The proteins migrate first through a conventional gradient gel, in which molecular friction increases as pore size decreases. The proteins then enter an inverted sodium dodecyl sulfate (SDS) gradient gel in which friction decreases; thus, smaller molecules gradually migrate faster and achieve improved separation from larger molecules, which remain near the border between the two gels. We therefore call this technique double-inverted gradient polyacrylamide gel electrophoresis (DG-PAGE). This technique was used to resolve mixtures of aldolase, horseradish peroxidase precursors, glucose 6-phosphate dehydrogenase and pyruvate kinase. By comparison with other established methods, we show that DG-PAGE has a higher resolving power, which achieves clear separation of proteins differing as little as 0.5 kDa in molecular weight.


Asunto(s)
Electroforesis en Gel de Poliacrilamida/métodos , Proteínas/aislamiento & purificación , Animales , Biotecnología , Fructosa-Bifosfato Aldolasa/aislamiento & purificación , Glucosafosfato Deshidrogenasa/aislamiento & purificación , Peroxidasa de Rábano Silvestre/aislamiento & purificación , Humanos , Peso Molecular , Proteínas/química , Piruvato Quinasa/aislamiento & purificación , Conejos , Dodecil Sulfato de Sodio
18.
FEMS Microbiol Lett ; 57(3): 307-11, 1989 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2656390

RESUMEN

5-Carboxymethyl-2-hydroxymuconic semialdehyde (CHMS) dehydrogenase from Escherichia coli C and Klebsiella pneumoniae M5a1 have been purified and some of their properties studied. The apparent Km values for NAD and CHMS were 11.7 +/- 1.5 microM and 5.2 +/- 1.9 microM, respectively, for the K. pneumoniae enzyme, and 19.5 +/- 2.7 microM and 9.2 +/- 1.4 microM, respectively, for the E. coli enzyme. Both enzymes were optimally active at pH 7.5 in sodium phosphate buffer. They had subunit molecular weights of 52,000 (+/- 1000) and the native enzymes appeared to be dimers of identical subunits. The first 20 residues of their N-terminal amino acid sequences were 90% homologous. A degenerate oligonucleotide probe constructed to a six amino acid sequence common to both enzymes gave strong hybridization with DNA from E. coli strains B and W as well as with E. coli C and K. pneumoniae but little or no hybridization to DNA from E. coli K12 or Pseudomonas putida.


Asunto(s)
Aldehído Oxidorreductasas/genética , Escherichia coli/enzimología , Klebsiella pneumoniae/enzimología , Aldehído Oxidorreductasas/metabolismo , Secuencia de Aminoácidos , Secuencia de Bases , ADN Bacteriano/genética , Escherichia coli/genética , Cinética , Klebsiella pneumoniae/genética , Datos de Secuencia Molecular , Peso Molecular , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie
19.
FEMS Microbiol Lett ; 126(3): 283-90, 1995 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-7729672

RESUMEN

We isolated 3-hydroxybenzoate-6-hydroxylase (E.C.1.14.13.), an inducible enzyme that catalyzed the para-hydroxylation of 3-hydroxybenzoate (3-HBA) to 2,5-dihydroxybenzoate, from Klebsiella pneumoniae. Although the enzyme was found to be mainly induced by its substrate, a coordinated induction of 3-hydroxybenzoate hydroxylase and gentisate dioxygenase was also observed in the presence of the product of the reaction. The purified enzyme was a monomer with a molecular mass of 42,000. It contained FAD as a prosthetic group, utilized NADH or NADPH with similar efficiencies and its activity was inhibited by Cu2+, Fe2+ and Hg2+. Other properties, such as induction mechanism and kinetic parameters were also studied. Moreover, for the first time the amino acid composition of a 3-hydroxybenzoate-6-hydroxylase was determined.


Asunto(s)
Proteínas Bacterianas/aislamiento & purificación , Dioxigenasas , Gentisatos , Klebsiella pneumoniae/enzimología , Oxigenasas de Función Mixta/aislamiento & purificación , Aminoácidos/análisis , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/química , Cationes Bivalentes/farmacología , Cromatografía por Intercambio Iónico , Dietil Pirocarbonato/farmacología , Inducción Enzimática/efectos de los fármacos , Flavina-Adenina Dinucleótido/metabolismo , Hidroxibenzoatos/metabolismo , Cinética , Oxigenasas de Función Mixta/antagonistas & inhibidores , Oxigenasas de Función Mixta/biosíntesis , Oxigenasas de Función Mixta/química , Peso Molecular , NAD/metabolismo , NADP/metabolismo , Oxigenasas/biosíntesis
20.
Biotechnol Prog ; 16(2): 287-91, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-10753456

RESUMEN

The stereospecific L-2-haloacid dehalogenase DehCI from Pseudomonas CBS3 was tagged with a peptide tail containing six histidines and overexpressed in Escherichia coli. The His-tagged protein was purified after a single-step affinity chromatography on Zn(2+)-chelating sepharose. The activity of the modified protein was tested after immobilization on Zn(2+)-chelating sepharose and on covalently bound acrylic polymer. Both immobilization systems were used for the transformation of racemic 2-chloropropionic acid into D-lactate and D-chloropropionic acid. Although immobilization on chelating sepharose produced a limited increase in stability, covalent immobilization on acrylic polymer significantly extended the operational temperature and pH range of the enzyme: up to 60% of activity was recovered at either 80 degrees C or pH 11, whereas no activity could be detected under these conditions in the soluble or chelate-immobilized enzyme. Both forms of immobilization extended the enzyme effective storage periods, and after 10 cycles of reutilization, 70% and 20% of the initial activity was recovered in the covalent- and chelate-immobilized enzyme, respectively.


Asunto(s)
Quelantes/química , Hidrolasas/química , Hidrolasas/metabolismo , Propionatos/metabolismo , Zinc/química , Estabilidad de Enzimas , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Histidina/genética , Hidrocarburos Clorados , Hidrolasas/genética , Cinética , Pseudomonas/enzimología , Pseudomonas/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo
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