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2.
Blood Cancer J ; 5: e345, 2015 Aug 28.
Article de Anglais | MEDLINE | ID: mdl-26314987

RÉSUMÉ

Monoclonal gammopathies of undetermined significance (MGUS) have been shown to be associated with an increased risk of fractures. This study describes prospectively the bone status of MGUS patients and determines the factors associated with vertebral fracture. We included prospectively 201 patients with MGUS, incidentally discovered, and with no known history of osteoporosis: mean age 66.6±12.5 years, 48.3% women, 51.7% immunoglobulin G (IgG), 33.3% IgM and 10.4% IgA. Light chain was kappa in 64.2% patients. All patients had spinal radiographs and bone mineral density measurement in addition to gammopathy assessment. At least one prevalent non-traumatic vertebral fracture was discovered in 18.4% patients and equally distributed between men and women. Fractured patients were older, had a lower bone density and had also more frequently a lambda light chain isotype. Compared with patients with κ light chain, the odds ratio of being fractured for patients with λ light chain was 4.32 (95% confidence interval 1.80-11.16; P=0.002). These results suggest a high prevalence of non-traumatic vertebral fractures in MGUS associated with lambda light chain isotype and not only explained by low bone density.


Sujet(s)
Gammapathie monoclonale de signification indéterminée/complications , Fractures du rachis/étiologie , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Femelle , Humains , Mâle , Adulte d'âge moyen , Gammapathie monoclonale de signification indéterminée/épidémiologie , Analyse multifactorielle , Prévalence , Études prospectives , Radiographie , Facteurs de risque , Fractures du rachis/imagerie diagnostique , Fractures du rachis/épidémiologie
3.
Peptides ; 30(2): 256-61, 2009 Feb.
Article de Anglais | MEDLINE | ID: mdl-19061927

RÉSUMÉ

Low circulating VVH7-like immunoreactivity (VVH7 i.r) level was amazingly observed in human diabetic sera. Here, we examined the impact of diabetes type, clinico-biological features and metabolic control on circulating VVH7 i.r level in this disease. ELISA test was used to measure VVH7 i.r in sera of 120 diabetic patients (type 1 diabetes in 64, type 2 diabetes in 56). Three enzymatic tests were also applied to determine serum cathepsin D (CD), dipeptidyl peptidase IV (DPP-IV) and angiotensin-converting enzyme (ACE) activities. A subgroup of 24 type 1 diabetic patients negative for microalbuminuria and hypertension were submitted to an ambulatory blood pressure monitoring to evaluate the relationship between VVH7 i.r level and blood pressure parameters. The mean serum concentration of VVH7 i.r was drastically reduced in diabetic patients (0.91+/-0.93 micromol/l versus 5.63+/-1.11 micromol/l in controls) (p<0.001). A negative correlation between VVH7 i.r level and daytime diastolic blood pressure existed in type 1 diabetic patients. There was no association of low VVH7 i.r with either type of diabetes or HbA1c level. An increase of cathepsin D activity was found in serum of diabetic patients compared to controls (0.47 U/ml versus 0.15 U/ml, respectively) whereas DPPIV activity was significantly decreased in diabetic sera (50.81 U/ml versus 282.10 U/l respectively). Diminution of VVH7 i.r in sera of diabetic patients was confirmed but still remained unexplained. Relationships between higher systolic blood pressure and decrease of VVH7 i.r reinforce the need to investigate this pathway in this disease to elucidate its role in macro- and micro-angiopathy.


Sujet(s)
Cathepsine D/métabolisme , Diabète de type 1/enzymologie , Diabète de type 2/enzymologie , Dipeptidyl peptidase 4/métabolisme , Fragments peptidiques/sang , Peptidyl-Dipeptidase A/métabolisme , Adulte , Sujet âgé , Pression sanguine/effets des médicaments et des substances chimiques , Diabète de type 1/sang , Diabète de type 1/métabolisme , Diabète de type 2/sang , Diabète de type 2/métabolisme , Femelle , Hémoglobines/immunologie , Hémoglobines/métabolisme , Humains , Mâle , Adulte d'âge moyen , Fragments peptidiques/immunologie
4.
Biochimie ; 86(1): 31-7, 2004 Jan.
Article de Anglais | MEDLINE | ID: mdl-14987798

RÉSUMÉ

Hemorphins are endogenous peptides belonging to the family of "atypical" opioid peptides released from sequentially hydrolyzed hemoglobin. In this paper, we report an inhibitory effect of these peptides on dipeptidyl peptidase IV (DPPIV) activity, known to be involved in regulatory functions such as the activation or inactivation of peptides. The structure activity research revealed that hemorphins N-terminus sequence influences nature of the interaction between hemorphins and DPPIV. Kinetic studies conducted with purified DPPIV demonstrated that hemorphin-7 (H7) constitutes a good substrate (K(cat)/K(m) of 137 mM(-1) s(-1)) for this enzyme but could also act as a selective competitive inhibitor by substrate binding site competition. These blood-derived peptides could represent endogenous regulators of this enzyme activity.


Sujet(s)
Dipeptidyl peptidase 4/métabolisme , Hémoglobines/métabolisme , Rein/enzymologie , Microsomes/enzymologie , Animaux , Dipeptidyl peptidase 4/composition chimique , Activation enzymatique/effets des médicaments et des substances chimiques , Antienzymes/métabolisme , Antienzymes/pharmacologie , Hémoglobines/composition chimique , Hémoglobines/pharmacologie , Mâle , Fragments peptidiques/métabolisme , Fragments peptidiques/pharmacologie , Liaison aux protéines , Rats , Rat Wistar , Spécificité du substrat
5.
Peptides ; 24(8): 1201-6, 2003 Aug.
Article de Anglais | MEDLINE | ID: mdl-14612192

RÉSUMÉ

The metabolism of LVVH7, an endogenous peptide obtained by cathepsin D hydrolysis of the beta chain of hemoglobin, was studied, in vitro, in the presence of cytosol of rat kidney and compared with angiotensin IV. High metabolic activity was found against these two peptides (half life time < 2 min) in this subcellular fraction. The main products of LVVH7 metabolism by renal cytosol are VVH7, H7 and LVVH6 suggesting both aminopeptidase and carboxypeptidase activities. The use of PEP inhibitor in kidney cytosol permitted to demonstrate the major role of prolyl endopeptidase (PEP) in LVVH7 degradation. This fact was reinforced by a kinetic study investigated with purified enzyme (Km/Vmax about 238 mM-1 s-1 and close to that observed for angiotensin related peptides).


Sujet(s)
Cytosol/métabolisme , Hémoglobines/métabolisme , Rein/métabolisme , Fragments peptidiques/métabolisme , Serine endopeptidases/métabolisme , Animaux , Techniques in vitro , Cinétique , Mâle , Prolyl-oligopeptidases , Rats , Rat Wistar , Spectrophotométrie UV , Facteurs temps
6.
Biochem Biophys Res Commun ; 281(3): 670-7, 2001 Mar 02.
Article de Anglais | MEDLINE | ID: mdl-11237710

RÉSUMÉ

Receptor binding properties of the hemoglobin-derived nonapeptide VV-hemorphin 7 (Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe-OH) were studied using both the unlabelled form and tritium-labelled derivative of the peptide. In binding studies using selective opioid radioligands, VV-hemorphin 7 exhibited a rank order of potency of mu > kappa >> delta. VV-hemorphin 7 was tritiated resulting in a compound with 1.03 TBq/mmol (27.8 Ci/mmol) specific radioactivity. The maximal number of binding sites was found to be 66.5 pmol/mg protein with an affinity of 82.1 nM in rat brain membranes. In competition studies, marked similarity was observed to the binding profile of the naturally occurring opioid heptapeptide Met-enkephalin-Arg-Phe (MERF) and its analogues to their naloxone-insensitive binding site. The common -Arg-Phe sequence at the carboxyl terminal end, which is similar to those of other endogenous peptides (-Arg-Phe-NH(2) in neuropeptide FF and FMRF-NH(2)) brings attention to the C-terminal end of the molecule and points to the possible existence of a common nonopioid binding site in mammals.


Sujet(s)
Hémoglobines/métabolisme , Fragments peptidiques/métabolisme , Séquence d'acides aminés , Animaux , Fixation compétitive , Encéphale/métabolisme , Guanosine 5'-O-(3-thiotriphosphate)/métabolisme , Hémoglobines/composition chimique , Données de séquences moléculaires , Fragments peptidiques/composition chimique , Dosage par compétition , Rats , Tritium
7.
J Dairy Res ; 67(1): 43-51, 2000 Feb.
Article de Anglais | MEDLINE | ID: mdl-10717842

RÉSUMÉ

This paper presents a novel contribution to the purification of goat beta-lactoglobulin by using an ultrafiltration membrane enzymic reactor. The basis of the purification process was the enzymic hydrolysis of contaminating proteins, alpha-lactalbumin and traces of serum albumin, by pepsin at 40 degrees C and pH 2, conditions under which beta-lactoglobulin is resistant to peptic digestion. Simultaneously, beta-lactoglobulin and peptides were separated by ultrafiltration. beta-Lactoglobulin was retained in the reactor while peptides generated by hydrolysis from alpha-lactalbumin and serum albumin permeated through the membrane. The process was made continuous by the addition of fresh whey to replace the lost permeate. Three mineral membranes with 10, 30 and 50 kDa molecular mass cut-off were tested and the 30 kDa membrane was selected for the continuous process. The simultaneous purification and concentration of beta-lactoglobulin from clarified goats' whey was achieved in a single step. The ultrafiltration membrane enzymic reactor could treat eight reactor volumes of clarified whey. The recovery of beta-lactoglobulin was 74%, its purity was 84% and its concentration 6.6-fold that in the initial clarified whey.


Sujet(s)
Capra , Lactoglobulines/isolement et purification , Protéines de lait/analyse , Pepsine A/métabolisme , Ultrafiltration , Animaux , Hydrolyse , Membrane artificielle , Masse moléculaire , Sérumalbumine/isolement et purification , Ultrafiltration/instrumentation , Protéines de lactosérum
8.
J Dairy Res ; 67(4): 551-9, 2000 Nov.
Article de Anglais | MEDLINE | ID: mdl-11131068

RÉSUMÉ

Goat whey was hydrolysed by pepsin in an ultrafiltration membrane enzymic reactor coupled with a 30 kDa mineral membrane. Peptides collected in the permeate were resolved using reversed-phase HPLC. Their sequences were determined by amino acid analysis, second order derivative spectra analysis and mass spectrometry. Owing to the resistance of beta-lactoglobulin (beta-lg) towards pepsin, the majority of peptides identified were derived from alpha-lactalbumin (alpha-la). Pepsin showed a broad specificity of hydrolysis sites and generated a wide range of products from dipeptides to very large peptides containing disulphide bridges. The molecular masses of peptides resulting from alpha-la degradation were between 150 and 6900 Da: 36% were < 600 Da. 24% were 600-2000 Da and 40% were > 2000 Da.


Sujet(s)
Capra , Lactalbumine/composition chimique , Protéines de lait/métabolisme , Pepsine A/métabolisme , Séquence d'acides aminés , Acides aminés/analyse , Animaux , Chromatographie en phase liquide à haute performance , Hydrolyse , Lactalbumine/isolement et purification , Spectrométrie de masse , Membrane artificielle , Protéines de lait/composition chimique , Masse moléculaire , RT-PCR , Spectrométrie de masse MALDI , Ultrafiltration , Protéines de lactosérum
9.
Prep Biochem Biotechnol ; 29(2): 189-202, 1999 May.
Article de Anglais | MEDLINE | ID: mdl-10231897

RÉSUMÉ

Bovine whey hydrolysate has been developed and applied to areas such as nutrition, culture media, and isolation of bioactive peptides. In order to produce such a type of hydrolysate, it is possible to use goat whey, which constitutes also a food processing by-product. Enzymatic hydrolysis of goat whey by pepsin was carried out in a continuous ultrafiltration reactor. The permeate contained peptide hydrolysate that was resolved by RPHPLC. Second order derivative spectroscopy, amino acid analysis, and mass spectrometry revealed the presence of a biologically active peptide called alpha-lactorphin. This constitutes preliminary information about goat whey enzymatic degradation for future applications.


Sujet(s)
Protéines de lait/composition chimique , Oligopeptides/synthèse chimique , Séquence d'acides aminés , Animaux , Chromatographie en phase liquide à haute performance , Capra , Hydrolyse , Spectrométrie de masse , Lait/composition chimique , Oligopeptides/analyse , Spectrophotométrie UV , Protéines de lactosérum
10.
FEBS Lett ; 447(1): 81-6, 1999 Mar 19.
Article de Anglais | MEDLINE | ID: mdl-10218587

RÉSUMÉ

Hemorphin generation by mice peritoneal macrophages has been recently reported, nevertheless no conclusive data exist to localize clearly the macrophage proteolytic activity implicated in their generation. Because lysosomes are believed to be the main site of degradation in the endocytic pathway, we have studied their potential implication in the generation of hemorphins from hemoglobin. When this protein is submitted to purified rat liver lysosomes, an early generation of hemorphin-7-related peptides, detected by a radioimmunoassay, was observed. These peptides seemed to be relatively stable during the first hours of hydrolysis.


Sujet(s)
Endopeptidases/métabolisme , Hémoglobines/biosynthèse , Hémoglobines/métabolisme , Foie/enzymologie , Lysosomes/enzymologie , Peptides opioïdes/biosynthèse , Fragments peptidiques/biosynthèse , Animaux , Hémoglobines/isolement et purification , Foie/cytologie , Macrophages/cytologie , Macrophages/enzymologie , Mâle , Peptides opioïdes/isolement et purification , Fragments peptidiques/isolement et purification , Rats , Rat Wistar , Spectrométrie de masse MALDI
11.
Peptides ; 19(8): 1339-48, 1998.
Article de Anglais | MEDLINE | ID: mdl-9809647

RÉSUMÉ

[125I]-Ang IV binding to rabbit collecting duct cell membranes was inhibited by hemorphins (H), a class of endogenous peptides obtained by hydrolysis of the beta chain of hemoglobin. The most potent competitors were those with a valine in their N-terminal part such as LVV-H7 and VV-H7 (IC50 = 1.3 nM) followed by VV-H8 and K6VV-H7 (5.1 nM). The same H, like Ang IV, interacted with aminopeptidase N (APN) as shown by their inhibitory effect (28-36%) on APN activity. HPLC analysis showed that only H with a N-terminal valine or leucine were hydrolyzed. Since H are detected in the body fluids, they are likely to act as endogenous competitors of Ang IV.


Sujet(s)
Angiotensine-II/analogues et dérivés , Antigènes CD13/métabolisme , Hémoglobines/pharmacologie , Fragments peptidiques/pharmacologie , Angiotensine-II/métabolisme , Animaux , Fixation compétitive , Cellules cultivées , Hémoglobines/métabolisme , Tubules collecteurs rénaux/cytologie , Tubules collecteurs rénaux/métabolisme , Fragments peptidiques/métabolisme , Lapins
12.
Biochem Biophys Res Commun ; 246(3): 719-24, 1998 May 29.
Article de Anglais | MEDLINE | ID: mdl-9618278

RÉSUMÉ

Hemorphin peptides, issued from hemoglobin, are emerging as endogenous bioactive peptides derived from in vivo tissular degradation of hemoglobin. In order to find the enzymes which could be implicated in the in vivo release of these peptides, the major lysosomal enzyme cathepsin D was selected, and a study of its activity towards hemoglobin and hemorphins was performed. In this paper, it is shown that according to the primary specificity of cathepsin D towards hemoglobin, this enzyme could constitute a good candidate for the in vivo release of two hemorphins: LVV-hemorphin-7 and VV-hemorphin-7. Moreover, these products, especially VV-hemorphin-7, are resistant to an extended cleavage by the enzyme. Although LVV-hemorphin-7 exhibits a lower resistance, an extended incubation with cathepsin D led to the release of the stable peptide VV-hemorphin-7.


Sujet(s)
Cathepsine D/métabolisme , Hémoglobines/métabolisme , Peptides opioïdes/métabolisme , Fragments peptidiques/métabolisme , Séquence d'acides aminés , Acides aminés/analyse , Animaux , Bovins , Chromatographie en phase liquide à haute performance , Hémoglobines/composition chimique , Données de séquences moléculaires , Fragments peptidiques/composition chimique , Maturation post-traductionnelle des protéines , Spécificité du substrat
13.
Peptides ; 19(4): 759-66, 1998.
Article de Anglais | MEDLINE | ID: mdl-9622033

RÉSUMÉ

In vitro human hemoglobin hydrolysis by cathepsin D was investigated. The quantitative evolution of neokyotorphin following the hydrolysis was determined by high-performance liquid chromatography coupled with a photodiode array detector. Spectral comparisons allowed us to identify neokyotorphin in the hydrolysates all along the hydrolysis. Second order derivative spectrometry was used in order to verify the presence of tyrosine in the peptide. This provided informations about the mechanism of cathepsin D activity towards hemoglobin. Moreover it confirmed that hemoglobin could appear as a precursor of some bioactive peptides following proteolytic degradation.


Sujet(s)
Cathepsine D/métabolisme , Endorphines/biosynthèse , Hémoglobines/métabolisme , Chromatographie en phase liquide à haute performance , Humains , Hydrolyse , Spectrométrie de masse MALDI , Spectrophotométrie
14.
Prep Biochem Biotechnol ; 28(1): 61-78, 1998 Feb.
Article de Anglais | MEDLINE | ID: mdl-9516643

RÉSUMÉ

Hemorphins extraction by organic solvents from a hemoglobin peptic hydrolysate was investigated. About thirteen solvents were used and only the aliphatic alcohols displayed selectivity for hemorphins. The resulting extracted phases, analyzed by SE-HPLC, RP-HPLC, and mass spectrometry, proved 1-butanol and 2-butanol to be the best extracting solvents towards hemorphins. The opioid activity test was carried out following each step of extraction and the obtained results were in agreement with a purification.


Sujet(s)
Hémoglobines/composition chimique , Stupéfiants/isolement et purification , Fragments peptidiques/isolement et purification , Alcools/métabolisme , Animaux , Bovins , Chromatographie en phase liquide à haute performance/méthodes , Cochons d'Inde , Hémoglobines/métabolisme , Iléum/effets des médicaments et des substances chimiques , Stupéfiants/analyse , Pepsine A/métabolisme , Fragments peptidiques/pharmacologie , Solvants/composition chimique , Spectrométrie de masse MALDI , Spectrophotométrie
15.
Neuropeptides ; 31(2): 147-53, 1997 Apr.
Article de Anglais | MEDLINE | ID: mdl-9179868

RÉSUMÉ

Two peptides, LVV-hemorphin-5 and VV-hemorphin-5, were isolated from a defined peptic bovine hemoglobin hydrolysate by reversed-phase HPLC. These peptides were identified as 31-38 and 32-38 fragments of beta chain of bovine hemoglobin. Their inhibitory activity towards angiotensin-converting enzyme and opioid potency were determined. Since their amino acid sequences show close homology with spinorphin, which is found in human cerebrospinal fluid and in the bovine spinal cord, the possible physiological role in vivo of these peptides was discussed.


Sujet(s)
Inhibiteurs de l'enzyme de conversion de l'angiotensine/pharmacologie , Hémoglobines/pharmacologie , Stupéfiants/pharmacologie , Fragments peptidiques/pharmacologie , Séquence d'acides aminés , Acides aminés/analyse , Inhibiteurs de l'enzyme de conversion de l'angiotensine/composition chimique , Inhibiteurs de l'enzyme de conversion de l'angiotensine/isolement et purification , Animaux , Bovins , Chromatographie en phase liquide à haute performance , Hémoglobines/composition chimique , Hémoglobines/isolement et purification , Humains , Stupéfiants/composition chimique , Stupéfiants/isolement et purification , Oligopeptides/liquide cérébrospinal , Oligopeptides/composition chimique , Pepsine A , Fragments peptidiques/composition chimique , Fragments peptidiques/isolement et purification , Peptidyl-Dipeptidase A/métabolisme , Inhibiteurs de protéases/liquide cérébrospinal , Inhibiteurs de protéases/composition chimique , Suidae
16.
Biopolymers ; 43(2): 75-98, 1997.
Article de Anglais | MEDLINE | ID: mdl-9216245

RÉSUMÉ

Investigation of hemoglobin peptic hydrolysate has revealed the presence of biologically active peptides with affinity for opioid receptors. Two peptides, VV-hemorphin-7 and LVV-hemorphin-7, were resolved by a combination of size exclusion and reversed phase HPLC. A new spectroscopic method based on the second order derivative spectra analysis of aromatic amino acids has been developed. This method allows qualitative and quantitative evaluation of hemorphins generated by peptic hemoglobin hydrolysis. Using this method, a kinetic study of hemorphins appearance has been undertaken. In this paper, we also evidenced the generation of VV-hemorphin-7 from globin by peritoneal macrophages. In regard to this result, the putative physiological role of hemorphins is discussed.


Sujet(s)
Hémoglobines/composition chimique , Peptides opioïdes/composition chimique , Fragments peptidiques/composition chimique , Séquence d'acides aminés , Animaux , Fixation compétitive , Endopeptidases/métabolisme , Hémoglobines/isolement et purification , Hémoglobines/métabolisme , Hémoglobines/pharmacologie , Hydrolyse , Macrophages péritonéaux/enzymologie , Macrophages péritonéaux/métabolisme , Données de séquences moléculaires , Antagonistes narcotiques/métabolisme , Antagonistes narcotiques/pharmacologie , Peptides opioïdes/isolement et purification , Peptides opioïdes/métabolisme , Peptides opioïdes/pharmacologie , Fragments peptidiques/isolement et purification , Fragments peptidiques/métabolisme , Fragments peptidiques/pharmacologie , Récepteurs aux opioïdes/métabolisme , Spectrométrie de masse FAB
17.
Peptides ; 18(2): 293-300, 1997.
Article de Anglais | MEDLINE | ID: mdl-9149303

RÉSUMÉ

In order to investigate the putative physiological role of the in vivo release of hemorphins from hemoglobin in tissues, an immunological approach was developed. Specific and sensitive antiserum were raised against the C-part of the V-V-hemorphin-7. The antisera recognized to the same extent the related hemorphins V-V-hemorphin-7 and L-V-V-hemorphin-7. The validity of our immunological approach was analyzed by studying the in vitro release of hemorphin from hemoglobin by cathepsin D and compared to the pepsin hydrolysis. These two enzymes led to the release of these same products suggesting that cathepsin D acted as an accurate pepsin-like enzyme. Moreover, considering the poor sensitivity of the available methods of detection for the in vitro Cathepsin D activity, our specific and sensitive V-V-hemorphin-7 radioimmunoassay seems to be a useful alternative assay for this enzymatic activity.


Sujet(s)
Cathepsine D/métabolisme , Hémoglobines/métabolisme , Fragments peptidiques/analyse , Fragments peptidiques/composition chimique , Séquence d'acides aminés , Animaux , Spécificité des anticorps , Bovins , Chromatographie en phase liquide à haute performance , Réactions croisées , Hydrolyse , Sérums immuns , Pepsine A/métabolisme , Fragments peptidiques/métabolisme , Dosage radioimmunologique , Sensibilité et spécificité
18.
Biotechnol Bioeng ; 52(4): 501-6, 1996 Nov 20.
Article de Anglais | MEDLINE | ID: mdl-18629922

RÉSUMÉ

Efficiency and selectivity of 30 and 150 kd inorganic ultrafiltration membranes (Techsep) toward tuna hemoglobin and myoglobin were studied. The influence of pH and ionic strength was investigated. Mass flow of myoglobin was higher at its isoelectric pH (8.6) and for low ionic strength (1.5 mM). This result was related to the absence of electrostatic repulsion between myoglobin and the surface of the dynamic membrane. The use of high ionic strength 0.15 M NaCl involved an apparent dimerisation of myoglobin and consequently a lower permeation through the membrane due to the molecular weight increase. The permeation and retention of hemoglobin did not agree with the effect of pH observed with myoglobin (best permeation at isoelectric pH) but followed the behavior of myoglobin. This was explained by a myoglobin concentration 10 times higher than hemoglobin concentration. The yield of retention selectivity was investigated. Selectivity of the membrane at pH 8.6 and 1.5 mM was favorable to myoglobin (increase of 40%) whereas a reversed selectivity was observed at pH 7.3, 0.15 M. (c) 1996 John Wiley & Sons, Inc.

19.
Appl Microbiol Biotechnol ; 45(6): 778-84, 1996 Jul.
Article de Anglais | MEDLINE | ID: mdl-8987469

RÉSUMÉ

A peptide with a bacterial-growth-stimulating activity was isolated from a bovine hemoglobin hydrolysate by reversed-phase high-performance liquid chromatography. Its primary structure and molecular mass, determined by amino acid analysis and fast-atom bombardment mass spectrometry, were identical to those of fragment 48-52 (Ser-Thr-Ala-Asp-Ala) of the beta chain of bovine hemoglobin. The microbiological tests in solid media demonstrated that this peptide exhibited a growth-stimulating activity on gram-negative bacteria.


Sujet(s)
Bactéries à Gram négatif/croissance et développement , Bactéries à Gram positif/croissance et développement , Substances de croissance/composition chimique , Substances de croissance/isolement et purification , Hémoglobines/composition chimique , Peptides/composition chimique , Peptides/isolement et purification , Acides aminés/analyse , Animaux , Bovins , Chromatographie en phase liquide à haute performance , Hydrolyse , Spectrométrie de masse
20.
Biochim Biophys Acta ; 1295(1): 73-80, 1996 Jun 07.
Article de Anglais | MEDLINE | ID: mdl-8679676

RÉSUMÉ

The kinetics of appearance of hemorphins during peptic hydrolysis of bovine hemoglobin was investigated by reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with a photodiode array detector. The degree of hydrolysis (DH) of hemoglobin by pepsin was determined and different defined DH of hydrolysates were obtained. The analysis of these hydrolysates by HPLC coupled with a photodiode array detector allowed us to identify and quantify the hemorphins in every hydrolysate and to determine the quantitative evolution of hemorphins as a function of DH. It indicated that hemoglobin was a direct precursor of LVV-hemorphin-5 and LVV-hemorphin-7. These peptides were demonstrated to be secondary substrates for pepsin to generate VV-hemorphin-5 and VV-hemorphin-7. Moreover, LVV-hemorphin-7 was more stable towards pepsin than LVV-hemorphin-5. The affinity of pepsin towards some peptidic bonds was also demonstrated.


Sujet(s)
Hémoglobines/métabolisme , Fragments peptidiques/métabolisme , Séquence d'acides aminés , Acides aminés/analyse , Animaux , Bovins , Chromatographie en phase liquide à haute performance/méthodes , Hydrolyse , Cinétique , Données de séquences moléculaires , Pepsine A/métabolisme
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