Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A marked increase in water permeability can be induced in Xenopus oocytes by injection of mRNA from tissues that express water channels, suggesting that the water channel is a protein. In view of this and previous reports which showed that proteinases may interfere with mercurial inhibition of water transport in red blood cells (RBC), we examined the influence of trypsin, chymotrypsin, papain, pronase, subtilisin and thermolysin on water permeability as well as on ATPase activity, H(+)-pump, passive H+ conductance, and Na+/H+ exchange in apical brush-border vesicles (BBMV) and endosomal (EV) vesicles from rat renal cortex. H+ transport was measured by Acridine orange fluorescence quenching and water transport by stopped-flow light scattering. As measured by potential-driven H+ accumulation in BBMV and EV, proteinase treatment had little effect on vesicle integrity. In BBMV, ecto-ATPase activity was inhibited by 15-30%, Na+/H+ exchange by 20-55%, and H+ conductance was unchanged. Osmotic water permeability (Pf) was 570 microns/s and was inhibited 85-90% by 0.6 mM HgCl2; proteinase treatment did not affect Pf or the HgCl2 inhibition. In EV, NEM-sensitive H+ accumulation and ATPase activity were inhibited by greater than 95%. Pf (140 microns/s) and HgCl2 inhibition (75-85%) were not influenced by proteinase treatment. SDS-PAGE showed selective digestion of multiple polypeptides by proteinases. These results confirm the presence of water channels in BBMV and EV and demonstrate selective inhibition of ATPase function and Na+/H+ exchange by proteinase digestion. The lack of effect of proteinases on water transport by mercurials. We conclude that the water channel may be a small integral membrane protein which, unlike the H(+)-ATPase and Na+/H+ exchanger, has no functionally important membrane domains that are sensitive to proteolysis.
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PMID:Proteinases inhibit H(+)-ATPase and Na+/H+ exchange but not water transport in apical and endosomal membranes from rat proximal tubule. 130 58

The major surface glycoprotein of Leishmania promastigotes, referred to as GP63, is a zinc metalloproteinase of 63,000 M(r) containing a glycosylphosphatidylinositol (GPI) membrane anchor. Recent studies demonstrated that recombinant GP63 (rGP63) expressed by the baculovirus insect cell system was secreted as a glycosylated latent proteinase that required activation for full proteinase activity (Button et al. (1993) Gene 134, 75-81). To extend these studies, the active site of L. major GP63 was characterized by site-directed mutagenesis and the activation mechanism of latent rGP63 was studied using both secreted and cell surface expression systems. To determine whether the proposed active site of L. major GP63 conforms to other well characterized zinc metalloproteinases, the proposed GP63 catalytic Glu-265, corresponding to catalytic Glu-147 of thermolysin, was changed to Asp-265. Using a transient expression system in COS-7 cells, expression of the Asp-265 mutant GP63 gene resulted in rGP63 with no detectable proteinase activity, whereas expression of the wild-type GP63 gene resulted in rGP63 with a level of proteinase activity similar to native GP63. Thus, the mechanism of GP63 proteinase activity is predicted to be homologous to that of other well characterized zinc metalloproteinases. NH2-Terminal sequence analysis revealed that activation with HgCl2 resulted in removal of the pro region, ultimately generating the mature NH2-terminus. This processing included the removal of a conserved Cys residue (Cys-48) and occurred by a cis mechanism, since the addition of previously activated rGP63 did not lead to an enhancement of latent rGP63 proteinase activation. The mechanism of activation of GP63 is consistent with the cysteine switch mechanism proposed for matrix metalloproteinases and thus has been conserved from protozoa to mammals.
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PMID:Analysis of the active site and activation mechanism of the Leishmania surface metalloproteinase GP63. 851 3

The proteolysis of flu virions of the strain A/Puerto Rico/8/34 (subtype H1N1) by enzymes of various classes was studied to develop an approach to the study of the structural organization and interaction of the basic protein components of the virion environment: hemagglutinin (HA), transmembrane homotrimeric glycoprotein, and matrix protein M1 forming a layer under the lipid membrane. Among the tested proteolytic enzymes and enzymic preparations (thermolysin, trypsin, chymotrypsin, subtilisin Carlsberg, pronase, papain, and bromelain), the cysteine proteases bromelain and papain and the enzymic preparation pronase efficiently deleted HA ectodomains, while chymotrypsin, trypsin, and subtilisin Carlsberg deleted only a part of them. An analysis by MALDI TOF mass spectrometry allowed us to locate the sites of HA hydrolysis by various enzymic preparations. Bromelain, papain, trypsin, and pronase split the polypeptide chain after the K177 residue located before the transmembrane domain (HA2 185-211). Subtilisin Carlsberg hydrolyzed the peptide bond at other neighboring points: after L178 (a basic site) or V176. The hydrolytic activity of bromelain measured by a highly specific chromogenic substrate of cysteine proteases Glp-Phe-Ala-pNA was almost three times higher in the presence of 5 mM beta-mercaptoethanol than in the presence of 50 mM. However, the complete removal of exodomains of HA, HA, and low-activity enzyme by the HA high- and low-activity enzyme required identical time intervals. In the absence of the reducing reagent, the removal of HA by bromelain proceeded a little more slowly and was accompanied by significant fragmentation of protein Ml1. The action of trans-epoxysuccinyl-L-leucylamido)butane (E-64), a specific inhibitor of cysteine proteases, and HgCl2 on the hydrolysis of proteins HA and M1 by bromelain was investigated.
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PMID:[Flu virion as a substrate for proteolytic enzymes]. 1867 93