Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.6.4 (chondroitinase)
 2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calpain I is a calcium-dependent cysteine proteinase that has been recently shown to degrade proteoglycan in vitro. The authors injected calpain I, which was purified from human red blood cells, into the intervertebral discs of rabbits. Roentgenograms showed disc space narrowing 1 week after the injection. Histologically, proteoglycan of the nucleus pulposus and anulus fibrosus decreased and notochordal cells in the nucleus pulposus almost disappeared. Biochemical data of the nucleus pulposus showed that the amounts of smaller proteoglycans increased 1 and 4 weeks after the injection. Eight weeks after the injection, histologic and biochemical data showed recovery compared with the data 1 week after injection. These findings show that calpain I is as potent an enzyme as chondroitinase ABC and has milder chemonucleolytic action than chymopapain. Regarding its possible clinical application, autogenous calpain I as purified from the patient's own red blood cells may have advantages over chymopapain and chondroitinase ABC in that it will prevent anaphylactic reaction.
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PMID:Chemonucleolysis with calpain I in rabbits. 843 17

Transforming growth factor-beta (TGF-beta) is normally secreted in a latent form, and plasmin-mediated proteolytic cleavage of latency-associated peptide (LAP), a component of latent TGF-beta complex that makes the complex inactive, activates latent TGF-beta. In the present study, we investigated the possible involvement of calpain, one of the cysteine proteases, in the activation of latent TGF-beta. When recombinant latent TGF-beta was incubated with calpain (1-10 u/ml) in a test tube, calpain cleaved LAP and released mature TGF-beta from the latent complex. When calpain was applied to cultured bovine capillary endothelial (BCE) cells, a low concentration of calpain (0.05-0.1 u/ml) inhibited the migration and proliferation of the cells, and these inhibitory effects were abrogated by anti-TGF-beta antibody as well as by calpain inhibitor peptide, but not by alpha2-antiplasmin, a specific inhibitor of plasmin. Active TGF-beta was detected in the conditioned medium of BCE cells collected in the presence of calpain. Chemical cross-linking of (125)I-calpain to BCE cells followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that calpain bound to the cell surface through chondroitinase ABC-sensitive proteoglycan. In addition, treatment of the BCE cells with chondroitinase ABC abrogated the inhibitory effect of calpain on the migration of these cells. Our data thus suggest that calpain is able to activate latent TGF-beta through a mechanism independent of plasmin. This activation is efficient in the presence of cells, and calpain binds to the cell surface via proteoglycan and activates latent TGF-beta, which is targeted to the same surface.
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PMID:Cell-associated activation of latent transforming growth factor-beta by calpain. 942 5