Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Meprin-a is a metalloendopeptidase present at high levels in the kidney brush border of some inbred mouse strains. Meprin-b is a latent metallo-endopeptidase, activated by trypsin-mediated proteolysis in vitro, that is present at similar activities (after activation) in all mouse strains. Meprin (a mixture of a and b forms) was purified from a high-meprin Mep-1a/a animal, and Lys-C peptides of this preparation were sequenced. The sequence data were used to direct the synthesis of peptides that were conjugated to albumin and used as immunogens. One of these antisera was specific to meprin-b and thus provided a specific tool to monitor expression of this form of meprin in different mouse strains.
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PMID:Immunological characterisation of different meprin species in mice. 188 59

1. Inbred mouse strains differ markedly in the expression of a kidney brush border metalloendopeptidase, meprin-a. 2. Brush border preparations from mice of the low-meprin-a phenotype (specific activities less than 5% of the high-meprin-a trait) contain a metallo-endopeptidase, meprin-b, that is larger than meprin-a, and which is inactive unless the membrane preparations are treated with trypsin. 3. This cryptic metallo-endopeptidase has been previously postulated to be a stalled precursor of meprin-a. 4. We show here that meprin-b is present in all mice-high and low meprin-a phenotypes--and that this activity is similar in substrate specificity and amount present in the brush border. 5. Meprin-b may therefore be a distinct gene product that is independent of meprin-a phenotype.
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PMID:A cryptic meprin-like proteolytic activity in mouse kidney brush border membranes. 228 66

Inbred mice can be phenotypically divided into two groups: those that contain high levels of a kidney metallo-endopeptidase activity (meprin-a) and those with low meprin-a activity. In studies to investigate the molecular basis for the heterogeneity in the expression of this proteinase activity, we found a latent metallo-proteinase activity associated with kidney membranes of C3H/HeJ mice, a low activity strain. The latent proteinase was activated by treatment of kidney brush border membranes with trypsin and was purified from solubilized C3H kidney membranes. Purified preparations of the C3H latent proteinase (referred to as meprin-b) contained three major proteins of subunit molecular weights 90,000, 140,000, and 160,000. In the absence of reducing agents, four 90,000-Da subunits are covalently linked by S-S bridges. The two higher molecular mass proteins are not covalently linked to each other or to the 90,000-Da subunits. However, cross-linking and affinity chromatography studies indicated that the proteins in the meprin-b preparation were tightly associated. By contrast, purified meprin-a contains only 85,000-Da subunit proteins linked by S-S bridges to form a tetramer. Endoglycosidase F treatment decreased the mass of the 90,000-Da meprin-b subunit and the 85,000-Da meprin-a subunit to polypeptides of 65,000-70,000 Da. The 90,000- and 85,000-Da subunits are immunologically similar, in that polyclonal antibodies prepared against one of the subunits cross-react with the other. The substrate specificities and inhibitor profiles of purified preparations of meprin-a and meprin-b are also similar. These data are consistent with the proposition that meprin-b is a polymorphic form of meprin-a that is incompletely processed in vivo.
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PMID:A latent proteinase in mouse kidney membranes. Characterization and relationship to meprin. 304 23