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)

Canine liver lysosomes were purified by sucrose discontinuous density gradient centrifugation and then ruptured by sonication to obtain the soluble fraction. This soluble lysosomal fraction, which contained a 25-fold increase in acid phosphatase activity per mg of total protein when compared with the original homogenate, was incubated with a subfraction (1.110 less than d less than 1.210 g/cm3, HDL3) of canine high density lipoproteins (HDL) at pH 3.8. HDL3 proteolysis by lysosomal proteases, measured as the release of peptides and amino acids by the ninhydrin reaction, followed hyperbolic curves with straight lines (r = 0.99) obtained on Lineweaver-Burk plots. Km calculated from the Lineweaver-Burk plot was 635 mug of HDL3 protein per 0.5 ml of incubation mixture. Optimum HDL3 proteolysis was observed from pH 3.8 to 4.5. Incubation with the other subcellular organelle fractions did not result in HDL3 proteolysis. To evaluate the effects of enzyme inhibitors, iodoacetate, p-chloromercuribenzoate (both specific for the endopeptidase, cathepsin B (EC 3.4.22.1)) and pepstatin (specific for the endopeptidase, cathepsin D (EC 3.4.23.5) were tested. Iodoacetate and p-chloromercuribenzoate inhibited HDL3 proteolysis 100% and bovine serum albumin proteolysis 65%. Pepstatin inhibited HDL3 proteolysis 45% and bovine serum albumin proteolysis 70%. The in vitro data presented support the hypothesis that hepatic lysosomes play an important role in HDL3 catabolism in the dog. Furthermore, results obtained from enzyme inhibition studies suggest that a specific lysosomal endopeptidase, cathepsin B, may play the key role in HDL3 proteolysis.
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PMID:Proteolysis of canine apolipoprotein by acid proteases in canine liver lysosomes. 17 45

A metal-dependent peptidase was isolated from the homogenate of human uterus by standard chromatographic techniques and purified to apparent homogeneity. The peptidase hydrolysed the synthetic vertebrate collagenase substrate 2,4-dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg (Dnp-peptide), the synthetic bacterial collagenase substrate 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-D-Arg (PZ-peptide) and gelatinolytic peptides of gelatin, but was inactive against collagen type I, gelatin and casein. The cleavage site for the Dnp-peptide was the Gly-Ile bond. The enzyme was not only inhibited by metal chelators, such as EDTA, 1,10-phenantroline and dithiothreitol but also by thiol reagents, such as mersalylic acid and N-ethylmaleimid. However, E-64, an inhibitor for thiolproteinases, and leupeptin, an inhibitor for thiol- and serine proteases, did not exhibit any inhibitory activity. Pepstatin, an inhibitor for aspartate proteinases, and inhibitors for serine proteinases like phenylmethanesulfonyl fluoride and Trasylol were ineffective as well. The purified peptidase displayed a single band in the SDS-PAGE with an apparent molecular mass of 65 kDa. Employing isoelectric focusing an IP of 5.0 could be determined. The enzyme's properties are discussed in relation to the proteinase EC 3.4.24.11 and to proteinases of the collagenase family as well as the possibility to discriminate these three metalloproteinase classes by employing the Dnp-peptide.
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PMID:Isolation and properties of a metal-dependent endopeptidase from human uterus hydrolysing synthetic collagenase substrates. 165 Feb 34

1. Lobster muscles contain a latent multicatalytic proteinase; heating at 60 degrees C for 1-2 min converts the latent form to a heat-activated form with enhanced proteolytic activity. Both forms have three endopeptidase activities, which are classified as the trypsin-like, chymotrypsin-like, and peptidylglutamylpeptide bond hydrolyzing activities. 2. Sulfhydryl reagents (mersalyl acid, N-ethylmaleimide, hemin, iodoacetamide, and p-chloromercurisulfonic acid), benzamidine, and chloromethyl ketones inhibited all three activities of the heat-activated form. Leupeptin and antipain inhibited only the trypsin-like activity, while the chymotrypsin-like activity was the most sensitive to diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, aprotinin, and soybean trypsin inhibitor. Pepstatin and L-trans-epoxysuccinylpeptides had little effect on the peptidase activities. 3. Sodium dodecyl sulfate and oleic acid preferentially activated the peptidylglutamyl-peptide hydrolyzing activity of the latent form, whereas N-ethylmaleimide stimulated both the trypsin-like and peptidylglutamyl-peptide hydrolases. These results suggest that the lobster enzyme is an atypical serine proteinase.
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PMID:Differential effects of oleic acid, sodium dodecyl sulfate, and protease inhibitors on the endopeptidase activities of the lobster multicatalytic proteinase. 176 21

An activity stain was used after native polyacrylamide gel electrophoresis, and at least 17 different endopeptidase activities were detected in maize (Zea mays L.) endosperm extracts prepared during the first 6 d after imbibition. The enzymes detected were classified into four groups based on their time of appearance and on their mobility in polyacrylamide gels. The first group, which included two enzymes present in dry endosperms, disappeared soon after imbibition. The second group, comprising five activity bands, appeared during the first 2 to 3 d after imbibition and then disappeared. The third set of enzymes increased continuously throughout the experimental period. The fourth group appeared after d 3 and remained at a constant level after that time. The endopeptidase activities were characterized by the effect of specific inhibitors on their activities. The two enzymes of the first group are metalloendopeptidases based on their sensitivity to ethylenediaminetetracetate (EDTA). Enzymes of the second, third, and fourth groups are sulfhydryl-endopeptidases as judged by their sensitivity to antipain, chymostatin, leupeptin, and E-64 and by their requirement for 2-mercaptoethanol. Pepstatin, phenylmethylsulfonyl fluoride, or EDTA had no effect on these enzymes. Many of the second, third, and fourth group enzymes cleaved [alpha]-zein-rich proteins as well as such easily obtained proteins as gelatin (used in our standard assay) and hemoglobin. The second group had a high affinity for [gamma]-zein, whereas none of the bands in the fourth group of enzymes cleaved this type of zein. The two metalloenzymes of the first group cleaved neither [alpha]- nor [gamma]-zeins.
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PMID:Development of Endopeptidase Activities in Maize (Zea mays L.) Endosperms. 1223 91