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)

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

The purification and characterisation of an extracellular endo and amino-peptidase of the marine Vibrio SA1 is described. The endopeptidase was purified by ammonium sulphate precipitation, gel filtration and affinity chromatography. It had a molecular weight of approximately 31,000, a pH optimum at 7.8 and a temperature optimum at 50 C. The enzyme was rapidly inactivated at 65 C. The aminopeptidase was purified by ammonium sulphate precipitation, gel filtration and preparative polyacrylamide gel electrophoresis. This enzyme had a molecular weight of approximately 21,000, a pH optimum at 8.6 and a temperature optimum at 60 C. Both proteases were inactivated by EDTA while reactivation occurred by Ca2+, Zn2+ and Mg2+ ions. The endopeptidase hydrolysed several peptide bonds in the oxidized B-chain of insulin, particularly those involving amino groups of hydrophobic amino acid residues with bulky side chains. It was unable to hydrolyse synthetic dipeptides, but a number of tripeptides were hydrolysed at a low rate. The aminopeptidase hydrolysed leucinamide and di- and tripeptides containing hydrophobic bulky amino acids as the N-terminal residue. It was concluded that the endopeptidase and the aminopeptidase of Vibrio SA1 possess complementary specificities.
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PMID:Purification and some properties of two extracellular proteolytic enzymes produced by Vibrio SA1. 3 29

1. Two new assay methods were developed for the lens proteinase. In both, the substrate was alpha2-crystallin (a major lens protein); in the first method, the products were detected by reaction with trinitrobenzenesulphonate in the presence of SO32-, whereas in the second method, 3H-labelled substrate was used, and the products were detected as radioactivity soluble in trichloroacetic acid. 2. The neutral proteinase from bovine lens was partially purified by extraction of the lens at pH5.0 and column chromatography on hydroxyapatite and Sepharose 6B gel. 3. The purified enzyme had no detectable activity against haemoglobin, azo-casein or gamma-crystallin under optimum conditions for alpha2-crystallin. 4. The enzyme showed greatest activity and stability at pH7.5. It was reversibly inhibited by EDTA and 1,10-phenanthroline, and activated by Ca2+ and Mg2+. 5. Molecular weights obtained for the enzyme by chromatography on Sepharose 6B were approx. 500,000 in buffer of I = 0.02, and 250,000 at I = 1.02. 6. The properties of the purified lens proteinase are such as to suggest that this enzyme could account for the entire endopeptidase activity of the lens.
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PMID:Metal-dependent proteinase of the lens. Assay, purification and properties of the bovine enzyme. 23 90

We have previously demonstrated the existence of two types of endopeptidase in Escherichia coli. A purification procedure is described for one of these, designated protease II. It has been purified about 13,500-fold with a recovery of 24%. The isolated enzyme appears homogeneous by electrophoresis and gel filtration. Its molecular weight is estimated by three different methods to be about 58,000. Its optimal pH is around 8. Protease II activity is unaffected by chelating agents and sulfhydryl reagents. Amidase and proteolytic activities are stimulated by calcium ion, which decreases the enzyme stability. Like pancreatic trypsin, this endopeptidase catalyses the hydrolysis of alpha-amino-substituted lysine and arginine esters. It appears distinct from the previously isolated protease I, which is a chymotrypsin-like enzyme. The apparent Michaelis constant for hydrolysis of N-benzoyl-L-arginine ethyl ester is 4.7 X 10(-4) M. The esterase activity is inhibited by diisopryopylphosphorofluoridate (Ki(app) equals 2.7 X 10(-3) M) and tosyl lysine chloromethyl ketone (Ki(app) equals 1.8 X 10(-5) M), indicating that serine and histidine residues may be present in the active site. However, protease II is insensitive to phenylmethanesulfonyl fluoride and several natural trypsin inhibitors. Its amidase and esterase activities are competitively inhibited by free arginine and aromatic amidines. The proteolytic activity measured on axocasein is very low. In contrast to trypsin, protease II is without effect on native beta-galactosidase. It easily degrades aspartokinase I and III. Nevertheless both enzymes are resistant to proteolysis in the presence of their respective allosteric effectors. These results provide further evidence that such differences in protease susceptibility can be related to the conformational state of the substrate. The possible implication of structural changes in the mechanism of preferential proteolysis in vivo, is discussed.
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PMID:Protease II from Escherichia coli. Purification and characterization. 24 Aug 39

Two reproducible techniques for the exsheathment in vitro of microfilariae of Brugia pahangi, and other sheathed microfilariae, are described. Microfilariae were isolated from infected cat blood by filtration and suspended in Hank's Balanced Salt Solution. The first technique involved the incubation of isolated microfilariae for one hour in 20 mM CaCl2 in a phosphate-free Balanced Salt Solution, during which time approximately 90% of the microfilariae lost their sheaths. The second method of exsheathing microfilariae of B. pahangi involved exposure of microfilariae to solutions of endopeptidase (5.8 units/ml) or papaya extract protease (3.0 units/ml) in Ca2+-free HBSS. Exsheathment rates of 95--100% occurred within 30 minutes in both enzyme solutions. Both the Ca2+ ion and the endopeptidase technique have proven equally effective in stimulating exsheathment of microfilariae of Brugia malayi, Wuchereria bancrofti and Litomosoides carinii. Such artificially exsheathed microfilariae are used for in vitro cultivation studies. The viability of Ca2+- and endopeptidase-exsheathed microfilariae of B. pahangi has been confirmed by inoculation of exsheathed larvae into susceptible female mosquitoes.
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PMID:The exsheathment of Brugia pahangi microfilariae under controlled conditions in vitro. 57 89

The dynamics of parathyroid hormone (PTH) biosynthesis, storage, and secretion in bovine parathyroid slices in vitro in response to alterations in the concentrations of extracellular calcium were studied. Hormone biosynthesis was evaluated by using polyacrylamide gel electrophoresis to measure incorporation of [3H]leucine into newly synthesized PTH and proparathyroid hormone (ProPTH) during short (35 min) incubations. Amounts of newly synthesized PTH stored in and secreted from the tissue slices were determined by electrophoretic analysis of [3H]PTH in extracts of tissue and media. Total PTH and ProPTH is slices and media were measured by specific radioimmunoassays. PTH secretion rates changes 5-fold when calcium was lowered from 2mM to 1mM. Secretion of some PTH continued despite high concentrations of calcium (5 mM). Biosynthesis of ProPTH was changed only slightly, and conversion of ProPTH to PTH was independent of the extracellular calcium concentration. Tissue stores of PTH increased during incubation of parathyroid slices in medium containing high amounts of calcium. The increase in stores was much less, however, than predicted by the findings of marked suppression of secretion and little change in rates of PTH biosynthesis. In high concentrations of calcium, a large fraction (up to 50%) of newly synthesized PTH was degraded within the tissue, whereas in low concentrations of calcium, little (less than 10%) of the PTH was degraded. No fragments of PTH or ProPTH were identified in either extracts of tissue or media, suggesting that degradation occurred rapidly by general proteolysis rather than by limited, specific endopeptidase activity. The data suggest that the parathyroid cell contains a calcium-sensitive degradative pathway for PTH and that this pathway may be involved in the regulation of hormone production and secretion.
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PMID:Calcium-dependent intracellular degradation of parathyroid hormone: a possible mechanism for the regulation of hormone stores. 115 61

Seven collagenases denoted by the letters alpha, beta, gamma, delta, epsilon, zeta and eta have been purified to homogeneity from the culture filtrate of Clostridium histolyticum. All seven enzymes are zinc proteinases that require calcium ions for activity and have essential carboxyl, tyrosyl and lysyl residues. These enzymes can be divided into two classes on the basis of the sequence homologies in their polypeptide chains, as revealed from a comparison of their tryptic digests. This division into classes is also supported by a comparison of their specificities toward peptide substrates, their interaction with substrate-analog inhibitors, and their mode of attack of triple helical collagens. The sequence specificities of these enzymes have been studied in detail. The specificities of the two classes are similar, but complementary. Both classes exhibit both endopeptidase and tripeptidylcarboxypeptidase activities, where the latter is thought to facilitate removal of Gly-X-Y triplets from the C-terminus of collagen fragments. The mode of attack of these collagenases on triple helical type I, II and III collagens is very similar for the enzymes within each class, but different for the two classes. The class I enzymes first hydrolyze loci near the ends of the triple helical domains of these collagen molecules, while the class II enzymes make their initial cleavages in the interior. The sites of these initial cleavages are being sequenced and preliminary results indicate that they do not resemble the tissue collagenase cleavage site with respect to either their imino acid content or distribution. The kinetic parameters for the hydrolysis of type I, II and III collagens have been measured and are similar in magnitude to those for the tissue collagenases. Synthetic peptide substrate-analog inhibitors have been prepared for both classes of collagenases and shown to be transition-state-analog inhibitors.
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PMID:Clostridium histolyticum collagenases: a new look at some old enzymes. 133 7

An endopeptidase cleaving specifically at the carboxyl side of acidic amino acid residues, preferentially at glutamic acid, has been isolated from a commercial extract obtained by fermentation with Bacillus licheniformis. Using ion-exchange chromatography and affinity chromatography on bacitracin-Sepharose, it was possible, from 100 ml commercial extract, to isolate 100 mg homogeneous enzyme in a yield of 50%. It is the first description of a large-scale isolation of a Glu/Asp-specific enzyme. The preparation was essentially free of contaminating activities. The isolated enzyme consists of one peptide chain of 222 amino acid residues and has a calculated molecular mass of 23,589 Da. The determined amino acid sequence shows similarity to the Glu/Asp-specific enzymes previously isolated from Staphylococcus aureus V8, Actinomyces sp. and Streptomyces thermovulgaris. The substrate preference of the enzyme has been investigated. Although non-specific cleavages were observed after prolonged hydrolysis at high enzyme concentrations the enzyme appears to be essentially specific for Glu-Xaa and Asp-Xaa, with strong preference for the former. The isolated enzyme exhibits a bell-shaped pH/activity profile with an optimum at pH 7.5-8.0. The activity is adversely affected by high ionic strength and beneficially affected by the inclusion of calcium ions in the assay medium. The enzyme is completely inhibited by diisopropylfluorophosphate, suggesting that it is a serine endopeptidase. It is partially inhibited by EDTA.
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PMID:Isolation and amino acid sequence of a glutamic acid specific endopeptidase from Bacillus licheniformis. 134 64

Diuretics have long been used to lower blood pressure in hypertensive patients or to control body fluid and electrolyte homeostasis in diseases such as congestive heart failure, chronic renal failure or cirrhosis. The initial response to diuretics is a negative sodium and fluid balance. The diuretic-induced loss of salt and water activates several hormonal systems such as vasopressin, the renin-angiotensin-aldosterone system or the sympathetic nervous system which tend to compensate for the changes in sodium and water balance. This neurohormonal response may have important clinical implications. Thus, the activation of the renin-angiotensin-aldosterone cascade appears to be partially responsible for the flat dose-blood pressure response curve of thiazides in hypertensive patients. It may also be responsible for the difference between responders and non-responders to diuretic therapy and for the development of side-effects such as hypokalaemia, metabolic alkalosis or hyponatraemia. There are several ways to prevent the undesirable consequences of the neurohormonal responses to diuretics. The first is to use low doses of these agents. It is also possible to combine them with agents that block the activity of the renin-angiotensin-aldosterone system such as ACE inhibitors or in combination with drugs that reduce aldosterone secretion such as calcium antagonists. The development of drugs able to enhance urinary sodium excretion and to reduce simultaneously the activity of the renin-angiotensin-aldosterone system may offer a new interesting alternative. This might perhaps be achieved in the future with the administration of neutral endopeptidase inhibitors which interfere with the enzymatic degradation of atrial natriuretic peptide.
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PMID:Neurohormonal consequences of diuretics in different cardiovascular syndromes. 136 43

A simple, rapid and sensitive assay for the type-1 endopeptidase (Arg-Arg cleaving) was developed by using an antiproinsulin monoclonal immunoadsorbent to separate reaction products from the substrate. The values obtained by this assay were identical with those obtained by an h.p.l.c.-based procedure and yielded similar values for the pH optimum (5.6) and Ca2+ activation (K0.5 = 2 mM). It was shown that the type-1 endopeptidase was readily solubilized by Triton X-114 (87 +/- 3%, n = 12) and partitioned principally into the aqueous phase at 30 degrees C (90.1 +/- 2.6%, n = 12). Activity was lost on gel filtration, but could be restored by adenosine 5'-[gamma-thio]triphosphate (K0.5 = 6 microM), 50 microM-dithiothreitol or 50 microM-Ca(2+)-trans-1,2-diaminocyclohexane-NNN'N'-tetra-acetic acid (CDTA), indicating that the enzyme was particularly sensitive to heavy metal ions. The Km obtained with proinsulin as substrate (13 +/- 1.7 microM) indicated that the enzyme works at close to its Vmax. in the nascent secretory granule. The Vmax. of the enzyme prepared from insulin granules (0.6% proinsulin converted/min) corresponded closely to the rate measured in vivo in rat islets. The type-1 endopeptidase also appears to be capable of binding to proinsulin in the region of the C-peptide/A-chain junction, since a peptide spanning this region was found to inhibit the 125I-proinsulin processing measured by this assay.
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PMID:Kinetic analysis of the type-1 proinsulin endopeptidase by a monoclonal antibody-based immunoadsorbent assay. 152 Feb 72


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