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1.
Zhonghua Yan Ke Za Zhi ; 55(9): 658-664, 2019 Sep 11.
Artigo em Zh | MEDLINE | ID: mdl-31495150

RESUMO

Objective: To evaluate the clinical effect of three-dimensional printing combined with surgical navigation and endoscopy for orbital fracture reconstruction. Methods: A case series study. Twenty-eight patients (28 eyes) with orbital fractures (20 males and 8 females, aged 10-61 years, with simple orbital fractures in 22 patients and composite orbital fractures in 6 patients) were treated with three-dimensional printing combined with surgical navigation and endoscopy for orbital fracture reconstruction at Affiliated Eye Hospital of Nanchang University from July 2016 to June 2018. With the help of three-dimensional printed models and guides, navigation positioning guidance and endoscopic visualization performance, the soft tissue incarcerated in the orbital fracture area was loosened, and the repair material was implanted (video attached). Postoperative follow-up was conducted at 1 week and 3 months. The follow-up observation included the best corrected visual acuity, diplopia, dyskinesia of the eyes, enophthalmos, and orbital volume. The data were analyzed by the paired t-test, Wilcoxon and the Mann-Whitney U rank sum test. Results: The best corrected visual acuity before and 1 week after surgery was 4.714±0.400 and 4.732±0.377, respectively, and the difference was not statistically significant (t=1.724, P=0.096). The enophthalmos before and 1 week after surgery was 2.2 (2.0-5.0) mm and 0.3 (0.0-2.3) mm, respectively, and the difference was significant (Z=-4.604, P<0.01). The orbital volume before and 1 week after surgery was 2 008.10 (6.84-11 200.00) mm(3) and 478.76 (5.01-7 286.00) mm(3), respectively, and the difference was statistically significant (Z=-3.735, P<0.01).The preoperative diplopia degree was 0, Ⅰ, Ⅱ, and Ⅲ in 14, 11, 3, and 0 eyes, while the degree of diplopia 3 months after surgery was 0, Ⅰ, Ⅱ, and Ⅲ in 22, 6, 0, and 0 eyes, respectively. The difference was statistically significant (Z=-2.359, P=0.018). The preoperative dyskinesia degree of the eyes was 0, Ⅰ, Ⅱ, and Ⅲ in 11, 11, 3, and 3 eyes, while the dyskinesia degree of the eyes 3 months after surgery was 0, Ⅰ, Ⅱ, and Ⅲ in 23, 5, 0, and 0 eyes, respectively. The difference was statistically significant (Z=-3.456, P=0.001). No implant infection, displacement, and other serious complications were observed during the follow-up of 3 to 12 months. Conclusions: Three-dimensional printing technology combined with nasal endoscopy and surgical navigation, which is applied in the reconstruction of orbital fracture, can significantly improve the symptoms of diplopia, ocular dyskinesia, and ocular depression. It is a feasible assistant method. (Chin J Ophthalmol, 2019, 55: 658-664).


Assuntos
Enoftalmia , Fraturas Orbitárias , Procedimentos de Cirurgia Plástica , Impressão Tridimensional , Adolescente , Adulto , Criança , Endoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Órbita , Fraturas Orbitárias/cirurgia , Tomografia Computadorizada por Raios X , Adulto Jovem
2.
Zhonghua Shao Shang Za Zhi ; 37(5): 453-459, 2021 May 20.
Artigo em Zh | MEDLINE | ID: mdl-34044527

RESUMO

Objective: To explore the clinical effects of anterolateral thigh perforator flap with sensory nerves in repairing the plantar skin and soft tissue defects. Methods: From January 2016 to March 2019, 13 male patients with plantar skin and soft tissue defects were admitted to the Department of Foot and Ankle Surgery of Ruihua Affiliated Hospital of Soochow University, aged 27 to 73 years. The retrospective cohort study was conducted. The wounds of 4 patients underwent 2 times of debridement. The wounds of 9 patients underwent 1 time of debridement and 1 or 2 time(s) of vacuum sealing drainage. Then all the wounds of patients were repaired with flaps when the wounds were clean and dry with no purulent exudation and were negative in secretion culture. The wound areas of this group of patients after wound debridement were 13.0 cm×5.5 cm to 36.0 cm×10.5 cm, and the wounds were repaired with anterolateral thigh perforator flaps with sensory nerves with area of 14 cm×6 cm to 37 cm×11 cm. The wound of 1 patient was repaired with a bilobed flap. The oblique or descending branch of the lateral circumflex femoral artery and its accompanying vein in the flap were anastomosed with the posterior tibial artery and its accompanying vein or the medial plantar artery and its accompanying vein in recipient sites. The lateral femoral cutaneous nerve in the flap was anastomosed with the recipient saphenous nerve or medial plantar cutaneous nerve. The donor sites were directly sutured. The survival of flaps and the healing of wounds in the donor and recipient areas were recorded, and the ulcers of the plantar repaired flap were followed up for 3 months after operation. The sensory function of the flap was evaluated by the sensory evaluation standard of British Medical Research Council (BMRC), and the ankle and foot function score system of American Orthopedic Foot and Ankle Society (AOFAS) was used for comprehensive functional evaluation at the last follow-up. Results: All the 14 flaps in 13 cases survived, and venous crisis occurred in two cases and the flaps survived smoothly after the venous re-anastomosis. One patient developed deep tissue infection after being discharged and was healed after secondary debridement. The donor and recipient areas of the remaining patients healed well. The patients were followed up for 6 to 18 months, the shape of flaps was slightly bloated in 5 patients, and the shape and texture of flaps in the other 8 patients were good. Six patients had ulcers in flaps at 3 months of follow-up after operation, which were healed after stopping weight-bearing activities. At the last follow-up, little linear scar hyperplasia could be seen in the donor site of patients; the BMRC sensory function evaluation results were S1 grade in 4 cases, S2 grade in 7 cases, and S3 grade in 2 cases; the AOFAS scores were excellent in 3 cases, good in 7 cases, fair in 2 cases, and poor in 1 case. Conclusions: The anterolateral thigh perforator flaps with sensory nerves can repair the plantar skin and soft tissue defects with the donor sites directly sutured and good shape of flaps, which provide a good treatment method for the recovery of plantar proprioceptive sensation and weight-bearing function.


Assuntos
Retalho Perfurante , Procedimentos de Cirurgia Plástica , Lesões dos Tecidos Moles , Humanos , Masculino , Estudos Retrospectivos , Transplante de Pele , Lesões dos Tecidos Moles/cirurgia , Coxa da Perna/cirurgia , Resultado do Tratamento
3.
J Phys Condens Matter ; 27(22): 225501, 2015 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-25985389

RESUMO

We report investigation of the structural phase transition and electronic properties of Hf(1-x)N (0 ⩽ x ⩽ 0.25) using first principles calculations. The defective NaCl-type structure with Hf vacancies (V(Hf)) is found to be stable over a large phase region. Hf3N4 with the Zr3N4-type structure is only stable in relative small region and readily destabilized when the stoichiometric ratio of N to Hf deviates from 4/3. The electronic and optic properties of Hf(1-x)N are controlled by the concentration of V(Hf). The full depletion of excess free electrons from Hf atoms results in the structural phase transition of Hf3N4.

4.
Biophys Chem ; 37(1-3): 31-41, 1990 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-2285793

RESUMO

Aspartate transcarbamylase (EC 2.1.3.2) from E. coli is a multimeric enzyme consisting of two catalytic subunits and three regulatory subunits whose activity is regulated by subunit interactions. Differential scanning calorimetric (DSC) scans of the wild-type enzyme consist of two peaks, each comprised of at least two components, corresponding to denaturation of the catalytic and regulatory subunits within the intact holoenzyme (Vickers et al., J. Biol. Chem. 253 (1978) 8493; Edge et al., Biochemistry 27 (1988) 8081). We have examined the effects of nine single-site mutations in the catalytic chains. Three of the mutations (Asp-100-Gly, Glu-86-Gln, and Arg-269-Gly) are at sites at the C1: C2 interface between c chains within the catalytic subunit. These mutations disrupt salt linkages present in both the T and R states of the molecule (Honzatko et al., J. Mol. Biol. 160 (1982) 219; Krause et al., J. Mol. Biol. 193 (1987) 527). The remainder (Lys-164-Ile, Tyr-165-Phe, Glu-239-Gln, Glu-239-Ala, Tyr-240-Phe and Asp-271-Ser) are at the C1: C4 interface between catalytic subunits and are involved in interactions which stabilize either the T or R state. DSC scans of all of the mutants except Asp-100-Gly and Arg-269-Gly consisted of two peaks. At intermediate concentrations, Asp-100-Gly and Arg-269-Gly had only a single peak near the Tm of the regulatory subunit transition in the holoenzyme, although their denaturational profiles were more complex at high and low protein concentrations. The catalytic subunits of Glu-86-Gln, Lys-164-Ile and Asp-271-Ser appear to be significantly destabilized relative to wild-type protein while Tyr-165-Phe and Tyr-240-Phe appear to be stabilized. Values of delta delta G degree cr, the difference between the subunit interaction energy of wild-type and mutant proteins, evaluated as suggested by Brandts et al. (Biochemistry 28 (1989) 8588) range from -3.7 kcal mol-1 for Glu-86-Gln to 2.4 kcal mol-1 for Tyr-165-Phe.


Assuntos
Aspartato Carbamoiltransferase/metabolismo , Escherichia coli/enzimologia , Mutagênese Sítio-Dirigida , Sequência de Aminoácidos , Análise de Variância , Aspartato Carbamoiltransferase/química , Aspartato Carbamoiltransferase/genética , Sítios de Ligação , Varredura Diferencial de Calorimetria , Escherichia coli/genética , Substâncias Macromoleculares , Dados de Sequência Molecular , Desnaturação Proteica
5.
J Chemother ; 3(6): 357-62, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1840274

RESUMO

The activity of clarithromycin and five other antimicrobial agents, namely amikacin, rifampicin, rifabutin, clofazimine and ciprofloxacin, was assessed both by an agar dilution and a radiometric method in broth on 11 Mycobacterium avium-intracellulare complex (MAC) strains, recently isolated from AIDS patients. Minimum inhibitory concentrations (MICs) radiometrically determined were, in general, several times lower than MICs assessed in agar, probably because of a partial degradation of antimicrobials during the long incubation period needed for tests in solid medium. When tested in broth, rifabutin and clofazimine showed very low MICs 90 (0.24 and 0.78 microgram/ml, respectively). Ciprofloxacin and clarithromycin also had MICs90 in the range of peak serum levels (1.93 and 3.76 micrograms/ml, respectively). Moreover, all these antimicrobials are known to concentrate several times in macrophages. MICs90 were higher for amikacin (11 micrograms/ml) and for rifampicin (8 micrograms/ml). When clarithromycin was tested against three MAC strains in combination with another drug, it showed a synergistic effect only when combined with rifampicin. Some synergistic effect was observed also when combining clarithromycin with rifampicin and amikacin, whereas in combination with rifabutin and clofazimine there was only an additive effect.


Assuntos
Síndrome da Imunodeficiência Adquirida/microbiologia , Antibacterianos/farmacologia , Eritromicina/análogos & derivados , Complexo Mycobacterium avium/efeitos dos fármacos , Amicacina/farmacologia , Ciprofloxacina/farmacologia , Claritromicina , Clofazimina/farmacologia , Sinergismo Farmacológico , Quimioterapia Combinada/farmacologia , Eritromicina/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Radiometria
6.
Pharmazie ; 58(10): 756-8, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14609292

RESUMO

Two new cyclopeptides, leiocyclocin C (1) and D (2), were isolated from the seeds of Goniothalamus leiocarpus (Annonaceae). Their structures were determined as cyclo-(Gly1-Ser-Pro2-Tyr2-Gly2-Tyr1-Pro1-Pro3) and cyclo-(Gly1-Leu-Pro1-Gly2-Phe-Tyr-Pro2), respectively, by means of spectral and chemical methods.


Assuntos
Annonaceae/química , Peptídeos Cíclicos/química , Espectroscopia de Ressonância Magnética , Extratos Vegetais/análise , Espectrometria de Massas de Bombardeamento Rápido de Átomos
7.
Yao Xue Xue Bao ; 36(4): 278-80, 2001 Apr.
Artigo em Zh | MEDLINE | ID: mdl-12580056

RESUMO

AIM: To study the chemical components of the root of Clematis chinensis. METHODS: Various chromatographic techniques were used to separate and purify the components. Their structures were determined on the basis of spectral and chemical evidence. RESULTS: Two compounds were isolated and elucidated as: clemaphenol A (I) and dihydro-4-hydroxy-5-hyroxymethy-2(3H)- furanone (II). CONCLUSION: Compound I and II are new compounds.


Assuntos
4-Butirolactona/isolamento & purificação , Anisóis/isolamento & purificação , Clematis/química , Furanos/isolamento & purificação , Plantas Medicinais/química , 4-Butirolactona/análogos & derivados , 4-Butirolactona/química , Anisóis/química , Furanos/química , Estrutura Molecular , Raízes de Plantas/química
8.
Yao Xue Xue Bao ; 29(11): 818-22, 1994.
Artigo em Zh | MEDLINE | ID: mdl-7863783

RESUMO

The effect of 15 stilbenoids on protein kinase C (PKC) was studied in order to search for naturally occurring PKC inhibitors. All these compounds were isolated from Chinese medicines. Three oligomeric stilbenes from Caragana sinica, alpha-viniferin, kobophenol A and miyabenol C, were shown to intensely inhibit the activity of partially purified rat brain PKC with IC50 values of 62.5, 52.0, and 27.5 mumol.L-1, respectively. Kinetic analyses revealed that that inhibition was noncompetitive. The other compounds also showed the effect. Monomer stilbenes exhibited PKC inhibitory activity at higher mumol.L-1 concentrations than oligomeric stilbenes. Whenever they are methylated or acetylated perfectly, the inhibition weakens or disappears.


Assuntos
Proteína Quinase C/antagonistas & inibidores , Estilbenos/farmacologia , Animais , Química Encefálica , Medicamentos de Ervas Chinesas/química , Masculino , Proteína Quinase C/isolamento & purificação , Proteína Quinase C/metabolismo , Ratos , Estilbenos/isolamento & purificação
9.
Yao Xue Xue Bao ; 32(7): 553-7, 1997 Jul.
Artigo em Zh | MEDLINE | ID: mdl-11596284

RESUMO

Sultamicillin is an oral mutual pro-drug composed of double esters of formaldehyde hydrate in which one of the hydroxyl groups is esterified with ampicillin and the other with sulbactam. It is hydrolyzed fast in neutral or weakly alkaline condition. When hydrolyzed, it forms ampicillin and hydroxylmethyl sulbactam or sulbactam and hydroxylmethyl ampicillin by different routes. Usually, the former has priority as the two ester bonds have different activities. The ratio of ampicillin to sulbactam in the products is about 3:1. Both the hydroxylmethyl sulbactam and the hydroxylmethyl ampicillin can be further catalyzed by esterase to produce formaldehyde.


Assuntos
Ampicilina/química , Pró-Fármacos/química , Sulbactam/química , Ampicilina/análise , Quimioterapia Combinada , Hidrólise , Sulbactam/análise
10.
Artigo em Zh | MEDLINE | ID: mdl-8044907

RESUMO

From 1989 to 1990, an investigation was conducted in three villages in Junsan township, Hanyang County, Hubei Province. The results showed that the infection rates of local residents were 55.1%, 49.5% and 44.3%, respectively; the EPG were 5.6, 5.2 and 2.0, respectively; the relative transmission index (RTI) were 7.1%, being highest in the age group 30-39 years. The relative index of potential contamination (IPC) was 67.2% in the age group 20-49 years, this group was considered as the main transmission source in the population. In animal hosts buffaloes, pigs and dogs, the infection rates were 35.7%, 60.0% and 75.0%, respectively; MPG (miracidium per gram), 0.4, 0.4 and 80.4, respectively; RTI (relative transmission index), 38.6%, 7.7 and 46.6%, respectively. The infection rates of pigs and dogs were high in Huangshi village, while the infection rate of buffaloes was high in Chuangjiang village. These results coincided with the transmission of schistosomiasis in these villages. The results showed that dogs as the main transmission sources had important significance in the epidemiology of schistosomiasis and that buffaloes and pigs herd and fed in the snail-habitats could be heavily infected.


Assuntos
Búfalos/parasitologia , Reservatórios de Doenças , Cães/parasitologia , Esquistossomose Japônica/transmissão , Suínos/parasitologia , Adolescente , Adulto , Animais , Criança , Pré-Escolar , China/epidemiologia , Feminino , Interações Hospedeiro-Parasita , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Ovos de Parasitas , Esquistossomose Japônica/epidemiologia
11.
Artigo em Inglês | MEDLINE | ID: mdl-23915026

RESUMO

Ovalbumin (OVA), one of the major allergens in hen egg white, and has widespread use in experimental models of allergy. The aim of this research was to assess the effect of glycation and heat treatment on the potential allergenicity of OVA prepared from hen egg white. Secondary and tertiary structures of OVA were also characterised to show the relationship between potential allergenicity and the conformation of OVA after heating and glycation. Glycation significantly reduced the potential allergenicity of OVA tested with egg allergy patients' sera, which was caused by conformation changes. An increased IgG reactivity was measured using rabbit anti-OVA and was supposed to be caused by protein unfolding which exposed hidden epitopes. Heating reduced the potential allergenicity of OVA at the expense of increased IgG reactivity. It is suggested that conformational changes of OVA induced by glycation and controlled heating significantly reduced its potential allergenicity.


Assuntos
Alérgenos/química , Alérgenos/imunologia , Proteínas Aviárias/química , Proteínas Aviárias/imunologia , Ovalbumina/química , Ovalbumina/imunologia , Alérgenos/efeitos adversos , Animais , Especificidade de Anticorpos , Proteínas Aviárias/efeitos adversos , Galinhas , Hipersensibilidade a Ovo/imunologia , Glicosilação , Temperatura Alta , Humanos , Imunoglobulina E/sangue , Ovalbumina/efeitos adversos , Conformação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Coelhos
16.
Lett Appl Microbiol ; 45(1): 62-7, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17594462

RESUMO

AIMS: To rapidly determine the causative agent of mass death in Lateolabrax japonicus in Zhelin Bay of Guangdong Province in China in April 2004. METHODS AND RESULTS: Thirty-six strains, numbered sequentially from RP01 to RP36, were isolated from six diseased fish. All of the strains were identified as being of the same vibrio species according to the results of universal primer PCR combined with DGGE (UPPCR-DGGE). RP30 was one of these strains that was randomly selected and analysed by using a morphological, physiological and biochemical plate, Biolog GN2 Microplate System and API 20E system. Furthermore, RP30' 16S rDNA was sequenced and aligned in Genbank. Its virulence to Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes) was also tested. RP30 is most closely related to four Vibrio ponticus strains (99.3% similarity). LD50s were 2.5 (x103 CFU per fish for intraperitoneal inoculation (IP) and 3.2 (x103 CFU per fish for intramuscular inoculation (IM), respectively. CONCLUSIONS: The investigated pathogenic agent of Lateolabrax japonicus (Cuvier in Cuvier and Valenciennes) was V. ponticus. SIGNIFICANCE AND IMPACT OF THE STUDY: UPPCR-DGGE is very helpful in epidemiologic investigation. Interestingly, this is the first report that V. ponticus infects cultured marine fish. DGGE was likewise first introduced to epidemiologic investigation of fish disease.


Assuntos
Aquicultura , Bass/microbiologia , Doenças dos Peixes/fisiopatologia , Vibrioses/veterinária , Vibrio/classificação , Vibrio/patogenicidade , Animais , Técnicas de Tipagem Bacteriana , Eletroforese em Gel de Poliacrilamida/métodos , Doenças dos Peixes/microbiologia , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Vibrio/genética , Vibrio/isolamento & purificação , Vibrioses/microbiologia , Vibrioses/fisiopatologia , Virulência
17.
Lett Appl Microbiol ; 41(2): 202-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16033522

RESUMO

AIMS: To investigate the distribution of the virulence of two Vibrio species among different strains obtained from the mariculture systems on the coast of Guangdong in China and the correlation between the virulence strains and the virulence genes among Vibrio alginolyticus. METHODS: Besides three strains, 72 V. alginolyticus strains and seven Vibrio parahaemolyticus strains were examined by PCR or semi-nested PCR for the virulence genes (tlh, trh, tdh, toxR, toxRS, ctxA, VPI). Additionally, the virulence of 18 V. alginolyticus strains was tested. SIGNIFICANCE AND IMPACT OF THE STUDY: Virulence genes homologous to those in the V. parahaemolyticus and Vibrio cholerae are widely distributed among V. alginolyticus and V. parahaemolyticus in the coastal mariculture systems in Guangdong, China. Some of the V. alginolyticus strains are pathogenic to aquatic animals, and might have derived their virulence genes from V. parahaemolyticus or V. cholerae, representing a possible reservoir of these genes. However, there is no correlation between presence and absence of the virulence genes used to investigate V. alginolyticus and its virulent strains. In this report, we also show that tlh is distributed among V. alginolyticus.


Assuntos
Genes Bacterianos , Água do Mar/microbiologia , Vibrio alginolyticus/genética , Vibrio alginolyticus/patogenicidade , Vibrio parahaemolyticus/genética , Vibrio parahaemolyticus/patogenicidade , China , Virulência/genética
18.
Biochemistry ; 26(1): 178-82, 1987 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-3548815

RESUMO

Enthalpies of binding of MgADP, MgATP, and 3-phosphoglycerate to yeast phosphoglycerate kinase have been determined by flow calorimetry at 9.95-32.00 degrees C. Combination of these data with published dissociation constants [Scopes, R.K. (1978) Eur. J. Biochem. 91, 119-129] yielded the following thermodynamic parameters for the binding of 3-phosphoglycerate at 25 degrees C: delta Go = -6.76 +/- 0.11 kcal mol-1, delta H = 3.74 +/- 0.08 kcal mol-1, delta So = 35.2 +/- 0.6 cal K-1 mol-1, and delta Cp = 0.12 +/- 0.32 kcal K-1 mol-1. The thermal unfolding of phosphoglycerate kinase in the absence and presence of the ligands listed above was studied by differential scanning calorimetry. The temperature of half-completion, t 1/2, of the denaturation and the denaturational enthalpy are increased by the binding of the ligands, the increase in t 1/2 being a manifestation of Le Chatelier's principle and that in enthalpy reflecting the enthalpy of dissociation of the ligand. Only one denaturational peak was observed under all conditions, and in contrast with the case of yeast hexokinase [Takahashi, K., Casey, J.L., & Sturtevant, J.M. (1981) Biochemistry 20, 4693-4697], no definitive evidence for the unfolding of more than one domain was obtained.


Assuntos
Fosfoglicerato Quinase/metabolismo , Saccharomyces cerevisiae/enzimologia , Varredura Diferencial de Calorimetria , Desnaturação Proteica , Termodinâmica
19.
Biochemistry ; 28(2): 813-8, 1989 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-2653429

RESUMO

In continuation of earlier work [Hu, C. Q., & Sturtevant, J.M. (1987) Biochemistry 26, 178-182], differential scanning calorimetry has been employed in a study of the effects on the thermal denaturation of yeast phosphoglycerate kinase of two inhibitors of the enzyme, sulfate ion and the dye Cibracron blue F3GA. Sulfate ion, as is usual with ligands that dissociate during unfolding of the host protein, raises t1/2, the temperature of half-completion of the denaturation, has only a modest effect, stemming from the enthalpy of dissociation of the ligand, on the enthalpy of denaturation, and has little or no effect on the heat capacity change resulting from denaturation. In sharp contrast, Cibacron blue F3GA lowers t1/2 and drastically decreases both the enthalpy and heat capacity changes due to denaturation. The DSC results with sulfate ion are consistent with previous kinetic data [Scopes, R. K. (1978) Eur. J. Biochem. 91, 119-129; Khamis, M. H., & Larsson-Raznikiewicz, M. (1981) Biochim. Biophys. Acta 657, 190-194], which indicate two binding sites for sulfate ion at one of which the ligand acts as a competitive inhibitor. The results with Cibacron blue F3GA indicate that the dye induces a major destabilizing structural change in the enzyme in addition to rendering it enzymically inactive.


Assuntos
Fosfoglicerato Quinase/metabolismo , Saccharomyces cerevisiae/enzimologia , Sulfatos/metabolismo , Triazinas/metabolismo , Varredura Diferencial de Calorimetria , Corantes , Cinética , Matemática , Modelos Teóricos , Ligação Proteica
20.
Biochemistry ; 31(44): 10699-702, 1992 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-1420185

RESUMO

In continuation of our earlier work on the effects of amino acid replacements on the thermodynamics of the thermal unfolding of T4 lysozyme [Kitamura, S., & Sturtevant, J. M. (1989) Biochemistry 28, 3788-3792; Connelly, P., Ghosaini, L., Hu, C.-Q., Kitamura, S., Tanaka, A., & Sturtevant, J. M. (1991) Biochemistry 30, 1887-1891; Hu, C.-Q., Kitamura, S., Tanaka, A., & Sturtevant, J. M. (1992) Biochemistry 31, 1643-1647], we report here a study by differential scanning calorimetry of the effects of five replacements at Ile3. Four of these replacements, those with Glu, Phe, Pro, and Thr, caused apparent destabilizations, while the replacement by Leu led to a small apparent stabilization. The largest observed destabilization (Ile3Pro) amounted to -3.0 kcal mol-1 in free energy at pH 2.00 and 38.8 degrees C (the denaturational temperature of the wild-type protein at this pH), and the largest stabilization amounted to +1.2 kcal mol-1 at pH 3.00 and 53.6 degrees C.


Assuntos
Bacteriófago T4/enzimologia , Varredura Diferencial de Calorimetria , Temperatura Alta , Muramidase/química , Dobramento de Proteína , Bacteriófago T4/genética , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Muramidase/genética , Mutação , Termodinâmica
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