Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An aminopeptidase was isolated from the culture filtrate of Clostridium histolyticum and purified to homogeneity. Absence of endopeptidase activity in the purified preparation was demonstrated. Gel filtration on a calibrated column indicates an apparent molecular weight of 340000 for the native enzyme. Gel electrophoresis of the denatured enzyme in the presence of dodecylsulfate in constant acrylamide concentration and in a concentration gradient, resulted in the appearance of a single component for which a molecular weight of 51000 and 59000 respectively, was calculated. From mobilities of crosslinked and denatured protein species a molecular weight of 56000 was obtained for the monomer. Specificity studies show that the enzyme cleaves all types of N-terminel amino acid residues including proline and hydroxyproline from small peptides and from polypeptides. The peptide bond formed between an N-terminal amino acid residue and proline is not cleaved by the enzyme. The combined action of aminopeptidase-P and clostridal aminopeptidase leads to complete hydrolysis of the proline-rich nonapeptide bradykinin. Low rates of hydrolysis was observed for charged residues, and amides of amino acids. Kinetic studies with five tripeptides of the general structure X-Gly-Gly, where X stands for Leu, Phe, Val, Ala, or Pro, show a decrease in Km with the increasing size of the hydrophobic side chain of X. The highest Kcat values are observed with proline and alanine. In the series Pro-Gly, Pro-Gly-Pro, Pro-Gly-Pro-Pro, the last peptide is the best substrate, indicating an active site complementary to at least four amino acid residues. The enzymatic activity is dependent on the presence of divalent cations, maximal activation being reached with Mn2+ and Co2+. The optimal pH for the Mn2+ and Co2+- activated enzyme is 8.6 and 8.2 respectively. The optimal temperature is 40 degrees C. Inhibition of the aminopeptidase was achieved with Zn2+, Cu2+ and p-mercuribenzoate, but not with diisopropylphosphofluoridate.
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PMID:An extracellular aminopeptidase from Clostridium histolyticum. 0 18

A number of biochemical properties have been investigated for both allelic and nonallelic forms of maize peptidases. Four aminopeptidases exist in maize (LAP-A, LAP-B, LAP-C, and LAP-D) and are the products of four diallelic loci. The aminopeptidases fall into two biochemical groups on the basis of these studies. LAP-A and LAP-D have comparatively low apparent Km (Kapp) values for arginine-naphthylamide derivatives and high velocities for arginine-naphthyl-amide and lysine-naphthylamide. LAP-B and LAP-C, on the other hand, have lower Kapp values for leucine-naphthylamide and higher velocities for nonpolar amino acid-naphthylamides than for arginine-naphthylamide. LAP-A and LAP-D are also relatively more heat stable than LAP-B and LAP-C and have somewhat higher molecular weights (71,500) than LAP-B and LAP-C (63,500). In determining molecular weights of the peptidases, use was made of their differential substrate specificities toward amino acid-naphthylamides. Some properties of genetically defined maize endopeptidase are also presented. Maize endopeptidase is inhibited by the sulfhydryl reagents N-ethylmaleimide and p-chloromercuribenzoate (pCMB), and by tosyl lysine chloromethyl ketone, Maize aminopeptidase activity is inhibited by N-ethylmaleimide, pCMB, and EDTA (ethylenediamine tetraacetic acid).
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PMID:Genetically defined peptidases of maize. I. Biochemical characterization of allelic and nonallelic forms. 1 Aug 84

The endopeptidase, post-proline cleaving enzyme, has been purified 10,500-fold in an overall yield of 18% from lamb kidney. The enzyme possesses a specific activity of 45 mumol/mg/min as tested with the substrate Z-Gly-Pro-Leu-Gly (Km = 6.0 X 10(-5)), has a molecular weight of 115,000, is comprised of two subunits with a molecular weight of 57,000, and exhibits maximal activity at pH 7.5 to 8.0. With the exception of the -Pro-Pro linkage, the -Pro-X-peptide bond (X equals L- and D-amino acid residues) located internally in the peptide sequence can be hydrolyzed (cleavage occurs faster when X = lipophilic side chain as compared to X = acidic side chain). The appropriate -Pro-X- bonds in zinc-free porcine insulin, oxytocin, arginine vasopressin, angiotensin II, bradykinin-potentiating factor were cleaved. Human gastrin, adrenocorticotropic hormone, denatured guinea pig skin collagen, and ascaris cuticle collagen were not degraded. Dipeptides with the structure Z-Pro-LD-X competitively inhibit post-proline cleaving enzyme.
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PMID:Post-proline cleaving enzyme. Purification of this endopeptidase by affinity chromatography. 1 73

PZ-peptidase is an endopeptidase that cleaves the synthetic substrate developed for clostridial collagenase, 4-phenylazobenzyloxycarbonyl-L-Pro-L-Leu-Gly-L-Pro-D-Arg (PZ-peptide). The peptidase has been purified to homogeneity from chicken embryos. The enzyme has a pH optimum of 7.5 to 8.5, and isoelectric point of 5.0, and a molecular weight of 77,000. The kinetic parameters at pH 8 and 37 degrees are: Km = 2 X 10(-4) M and Vmax = 4.2 mumol/min/mg of protein. The enzyme is inhibited by p-hydroxymercuribenzoate (100%), N-ethylmaleimide (60%), and chelating agents (40 to 60%). Maximum activity is attained in the presence of reducing agents and Ca2+, Sr2+, or Mg2+. The peptidase has no detectable action on casein, serum albumin, collagen, collagen alpha chains, various collagen peptides (alpha1)(I)-CB2, alpha1(I)-CB3, alpha1(I)-CB4), (Gly-Pro-Pro)10, or (Gly-Pro-Pro)5. It does catalyze the hydrolysis of the Hyp--Gly bond in the 17-residue collagen peptide alpha1(II)-CB6-C2 and it partially digested a mixture of collagen peptides of molecular weight 350 to 2500. A role of this peptidase in collagen breakdown appears to be restricted to a late stage when degradation products would fall in the range of 5 to 30 residues.
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PMID:PZ-peptidase from chick embryos. Purification, properties, and action on collagen peptides. 1 6

An endopeptidase from the larvae of the hornet Vespa crabro has been purified to homogeneity. The enzyme has been characterized with respect to molecular weight, amino acid compositon, and amino- and carboxyl-terminal sequences. The catalytic properties of the hornet protease are similar to those of bovine chymotrypsin with respect to inactivation by phenylmethanesulfonyl fluoride and carbobenzoxyphenylalanine chloro ketone and preferential peptide bond cleavage at aromatic amino acid residues. In contrast to bovine chymotrypsin, the hornet protease is not inhibited by the basic pancreatic Kunitz inhibitor, soybean inhibitor, or chicken ovomucoid. The molecular weight, as determined by several independent methods, was found to be 14 500. The protease is a single-chain protein containing two disulfide bonds. The terminal sequences are: NH2-Ile-Val-Gly-Gly-Ile-Asp.....Gly-Lys-Tyr-Pro-Tyr-Gln-Val-Ser-Leu-Arg-COOH.
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PMID:Enzymatic and chemical properties of an endopeptidase from the larva of the hornet Vespa crabro. 10 67

1. The synthetic peptide, 2,4-dinitrophenyl-L-Pro-L-Leu-Gly-L-Ile-L-Ala-Gly-L-Arg-amide (DNP-peptide) was tested as a potential substrate for uterine collagenase. Rat uteri were homogenized and the insoluble fraction was extracted at 60 degrees C to obtain collagenase. The extracts were chromatographed on Sephadex G-150 to yield two peaks of DNP-peptide hydrolyzing activity. Peak I was completely inhibited by EDTA and had a molecular weight greater than 100 000. Peak II was inhibited about 90% by EDTA and had an apparent molecular weight of about 70 000. 2. Peak II coincided closely, but not exactly, with the peak of collagenase activity. It differed from collagenase in heat stability, binding properties on CM-Sephadex and failure to display latency. 3. Peak II represents a new endopeptidase activity. It has a pH optimum of 7 and it cleaves the DNP-peptide at the Gly-Ile and, possibly, the Leu-Gly bond. 4. The DNP-peptide is not a satisfactory substrate for the assay of impure collagenase preparations nor does it inhibit the action of collagenase on collagen substrate when added in 30-fold molar excess.
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PMID:Separation of collagenase and a metal-dependent endopeptidase of rat uterus that hydrolyzes a heptapeptide related to collagen. 22 33

Radioactive alpha factor is degraded to discrete biologically inactive fragments by the target a cells of S. cerevisiae, but not by alpha cells which make the pheromone. The pattern of cleavage products and sequence analysis of one fragment indicated that the first scission occurred between leucine 6 and lysine 7. The protease inhibitors tosyl-L-argininyl-methyl ester (TAME), tosyl-L-lysyl-chloromethylketone (TLCK) and N-acetyl-L-leucyl-L-leucyl-L-argininal (leupeptin) markedly prolonged the period of G1 arrest in a cells exposed to alpha factor, while other standard protease inhibitors had little or no effect. The presence of TAME and leupeptin, or TLCK, reduced the rate of degradation of radioactively labeled alpha factor by a cells. Intact yeast cells have apparent esterase and amidase activities that are blocked by the same spectrum of inhibitors that potentiate alpha factor action. Purified alpha factor is a competitive inhibitor of these hydrolytic activities. The activities are present in yeast mutants which have greatly reduced levels of the three major vacuole-associated proteases (A, B and C) or which carry an ochre mutation in the major neutral protease (B). These observations indicate that the inactivation of alpha factor is due to endoproteolytic cleavage, the destruction of the pheromone is required to overcome its effects on growth and that degradation of the molecule may involve surface bound endopeptidase(s).
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PMID:Recovery of S. cerevisiae a cells from G1 arrest by alpha factor pheromone requires endopeptidase action. 39

Two arylamidases (I and II) were purified from human erythrocytes by a procedure that comprised removal of haemoglobin from disrupted cells with CM-Sephadex D-50, followed by treatment of the haemoglobin-free preparation subsequently with DEAE-cellulose, gel-permeation chromatography on Sephadex G-200, gradient solubilization on Celite, isoelectric focusing in a pH gradient from 4 to 6, gel-permeation chromatography on Sephadex G-100 (superfine), and finally affinity chromatography on Sepharose 4B covalently coupled to L-arginine. In preparative-scale purifications, enzymes I and II were separated at the second gel-permeation chromatography. Enzyme II was obtained as a homogeneous protein, as shown by several criteria. Enzyme I hydrolysed, with decreasing rates, the L-amino acid 2-naphtylamides of lysine, arginine, alanine, methionine, phenylalanine and leucine, and the reactions were slightly inhibited by 0.2 M-NaCl. Enzyme II hydrolysed most rapidly the corresponding derivatives of arginine, leucine, valine, methionine, proline and alanine, in that order, and the hydrolyses were strongly dependent on Cl-. The hydrolysis of these substrates proceeded rapidly at physiological Cl- concentration (0.15 M). The molecular weights (by gel filtration) of enzymes I and II were 85 000 and 52 500 respectively. The pH optimum was approx. 7.2 for both enzymes. The isoelectric point of enzyme II was approx. 4.8. Enzyme I was activated by Co2+, which did not affect enzyme II to any noticeable extent. The kinetics of reactions catalysed by enzyme I were characterized by strong substrate inhibition, but enzyme II was not inhibited by high substrate concentrations. The Cl- activated enzyme II also showed endopeptidase activity in hydrolysing bradykinin.
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PMID:Purification and characterization of two human erythrocyte arylamidases preferentially hydrolysing N-terminal arginine or lysine residues. 74 27

1. Cathepsin H is an endoaminopeptidase belonging to the group of thiol enzymes. It was purified from rat liver lysosomes by gel filtration on Sephadex G-75, chromatography on CM-Sephadex C-50, on DEAE-Cellulose DE-52 and subsequently on an organomercurial absorbent. 2. The molecular weight of cathepsin H was found to be 28,000 and the isoelectric point was estimated to be at pH 7.1 by analytical isoelectric focusing. 3. Cathepsin H has to be designated as endoaminopeptidase, because it catalyzes the hydrolysis of proteins, N-terminal substituted proteins and amino acid derivatives, respectively, as well as of peptides of various chain length and N-terminal free amino acid derivatives. Cathepsin H shows amidase and esterase activity, but it does not show carboxypeptidase activity. The finding of the amino- and endopeptidase nature of cathepsin H has been revealed mainly by the results obtained with inhibitors and by the rather high temperature stability of the enzyme. The chlormethyl ketone of leucine proves to be the strongest inhibitor of the aminopeptidase as well as of the endopeptidase activity, whereas leupeptin endopeptidase activity and endopeptidase substrates inhibit competitively the aminopeptidase activity. 5. Cathepsin H shows highest activity at pH 6.0 in the presence of 1--5 mM GSH and EDTA. 6. The enzyme is stable for several months at slightly acid pH values in a deep frozen state.
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PMID:Cathepsin H: an endoaminopeptidase from rat liver lysosomes. 90 30

The sequence of the amino-terminal portion of human parathyroid hormone, particularly the identity of residues 22, 28, and 30 (the subject of discrepancies in recent published reports), has been reexamined by two basic methods of structural analysis. A fresh lot of human parathyroid hormone isolated from pooled adenoma tissue was analyzed by Edman degradation with identification of critical residues by thin-layer chromatography and gas-liquid chromatography. In the second approach, -14C or tritiated amino acids were incorporated during biosynthesis of the human hormone in slices of parathyroid glands in vitro; the appropriate amino acid residues were then determined as the -14C or tritiated phenythiohydantoin derivatives of the amino acid after Edman degradation, or by peptide isolation after appropriate cleavage with endopeptidase, or both. The results confirm our previous findings that residue 22 is glutamic acid, residue 28 is leucine, and residue 30 is aspartic acid.
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PMID:A reinvestigation of the amino-terminal sequence of human parathyroid hormone. 112 1


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