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)

A calcium-activated neutral proteinase (CANP)-specific endogenous inhibitor (calpastatin) was purified from bovine brain by successive column chromatography. The purified inhibitor exhibited a major band on sodium dodecylsulfate polyacrylamide gel electrophoresis with an approximate molecular weight of 68 kD. The polyclonal antisera raised to the inhibitor strongly reacted with the 68 kD protein band. Two lightly stained bands approximately 55-68 kD and 120-130 kD were also recognized by the inhibitor antiserum. The inhibitor specifically inhibited CANP activity and the half-maximal inhibition was found with 75 ng of calpastatin per 1 micrograms of CANP in a final volume of 125 microliters. Cathepsin B and papain were not inhibited by the inhibitor, while trypsin and chymotrypsin were inhibited to some extent. The inhibitor formed a complex with CANP and the inactive complex was dissociated into active fractions of enzyme and calpastatin in the presence of EGTA.
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PMID:Purification of an endogenous 68 kD inhibitor of calcium-activated neutral proteinase (CANP) from bovine brain: immunoblot identification and characterization. 231 18

This paper describes the isolation, purification and properties of a specific inhibitor of calcium-activated neutral proteinase (CaANP) in rabbit skeletal muscle. The inhibitor was a thermo-acid-stable protein degraded by trypsin and chymotrypsin and seemed to contain two polypeptide chains with molecular weights of 70 000 and 13 000 daltons. Maximal inhibitory activity was obtained at neutral pH. High salt concentrations were needed to suppressinhibition. Inhibitor concentration had no effect on the optimal Ca++ ion levels for CaANP. These experiments also show that enzyme inhibitor association was instantaneous and did not need any incubation.
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PMID:Characterization and purification of a Ca2+ ion-activated neutral proteinase inhibitor in rabbit skeletal muscle. 629 43

The cytotoxicity of an endogenous inhibitor of calcium-activated neutral proteinase (CANP-I) was evaluated using various mammalian tumor-derived cell lines and human cell cultures. The inhibitor was selectively cytotoxic to human tumor cells from lung, bladder, melanoma and chronic myeloid leukemia tissues, in a dose-dependent manner, and was also cytotoxic to Walker rat tumor cells. The inhibitor was not cytotoxic to normal human, urothelial, fallopian tube, liver and resting white blood cells. Cytological examination of the treated malignant cells revealed cells with vacuolated cytoplasm, pyknotic, hyperchromatic nuclei and membranous, granular haematoxylinophilic extracellular matrix. The use of the inhibitor on urothelial tumor tissues caused great exfoliation of necrotic cells while not affecting normal urothelial tissues. When the inhibitor was tested on mixed cell cultures, consisting of normal and malignant cell clones, a selective cytotoxicity to the malignant cells occurred allowing the normal cells to grow unaffected. Cytogenetic and cytological examination of the remaining cells, after the inhibitor treatment, showed normal diploid karyotype and morphology. The inhibitor was also tested in vivo on Wistar rats bearing Walker tumors. Treatment with 50 Units/100 g i.p. daily for 5 days caused 90% tumor regression and necrosis of metastatic foci in the liver and abdomen, without toxic side effects. The protease inhibitors trypsin-chymotrypsin, aprotinin, leupeptin and E64 were also tested in vitro and showed no anticancer activity. In conclusion, the endogenous inhibitor of CANP selectively killed malignant cells of different chromosomal abnormalities, tissue and species origin; also nuclear vlimata and chemoresistant cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The selective anticancer activity of the endogenous inhibitor of calcium-activated neutral proteinase. A histological, cytological and chemosensitivity study. 798 96