Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ca2+-Requiring proteases degrade cytosolic and integral membrane proteins as well as alter, by limited proteolysis, the activity of certain protein kinases. When cells are lysed, a Ca2+-requiring protease degrades the epidermal growth factor (EGF) receptor, an integral membrane protein with an intrinsic kinase activity, from its 170-kDa form to a 150-kDa form. This Ca2+-requiring protease has all of the characteristics of calcium-activated neutral protease (CANP). To show that CANP is the protease uniquely responsible for the degradation of the native EGF receptor in vitro, CANP was highly purified from beef lung. This affinity purified CANP had properties previously described for other CANPs: heterodimer of 80 and 30 kDa; neutral pH optimum; activation by millimolar Ca2+; and inhibition by an endogenous, heat-stable proteinaceous inhibitor, by leupeptin, and by sulfhydryl alkylating agents. Using the EGF receptor labeled by covalent attachment to 125I-EGF, this purified CANP quantitatively generated the 150-kDa form from the native receptor in A-431 cell membranes. As with the native receptor, the 150-kDa receptor forms produced by the endogenous Ca2+-requiring protease, by CANP, by chymotrypsin, and by elastase were all capable of EGF-stimulated autophosphorylation. When the 150-kDa receptor forms were generated by the three exogenously added proteases, autophosphorylation with [gamma-32P]ATP followed by trypsinization produced 32P-labeled peptides that were not the same. However, the tryptic 32P-labeled peptides from the autophosphorylated 150-kDa receptor form produced by CANP or by the endogenous Ca2+-requiring protease were identical. These data indicate that CANP is identical to the endogenous Ca2+-requiring protease responsible for producing the autophosphorylating 150-kDa receptor form from the native EGF receptor when cells are lysed.
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PMID:Calcium-activated neutral protease purified from beef lung: properties and use in defining structure of epidermal growth factor receptors. 299 27

We have identified and isolated two new calcium-activated neutral hydrolases from human ventricular muscles. The one is an esterase, of which molecular weight was 300,000, required millimolar concentration of Ca2+, hydrolyzed Ac-Tyr-OEt X H2O, optiaml pH at 7.0. The other is an amidase, of which molecular weight was 70,000, also required millimolar concentration of Ca2+, hydrolyzed a synthetic substrate for chymotrypsin, Suc-Leu-Leu-Val-Tyr-MCA, with optimal pH at 7.2. Both enzymes did not degrade casein or contractile proteins (myosin, actin, troponin and tropomyosin). Their activities were not inhibited by exogenous protease inhibitors, leupeptin, antipain, monoiodoacetic acid and chymostatin, while the amidase activity was blocked by the endogenous inhibitor against calcium-activated neutral protease (CANP). Thus, their characters are different from chymotrypsin or CANP and they seems to be new hydrolases in the human heart.
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PMID:Identification of two new calcium dependent hydrolases in the human heart. 301 Sep 97

An endogenous inhibitor of calcium-activated neutral protease (CANP), which was isolated from rabbit skeletal muscle under mild conditions, comprised high- and low-molecular-weight components. The latter (LMW-inhibitor; Mr=50,000) was purified to homogeneity by means of chromatography on DEAE-cellulose and phenyl-Sepharose CL-4B and chromatofocusing. The purified inhibitor is a protein composed of two polypeptide chains with molecular weights of 26,000 and 24,000 daltons. It contains large amounts of glutamic acid, alanine, and serine, and small amounts of aromatic amino acids. It was specific for CANPs having low (m-type) and high (mu-type) Ca2+-sensitivity, had no effect on any other protease examined (trypsin, alpha-chymotrypsin, bromelain, ficin, papain, thermolysin, etc.), and inhibited rabbit mCANP more effectively than rabbit muCANP or chicken mCANP. It was demonstrated that the inhibition is due to the formation of a stoichiometric complex between two molecules of rabbit mCANP and one inhibitor molecule.
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PMID:Purification and characterization of an inhibitor of calcium-activated neutral protease from rabbit skeletal muscle: purification of 50,000-dalton inhibitor. 609 76

An endogenous inhibitor of calcium-activated neutral protease was purified to homogeneity from rabbit skeletal muscle using ion-exchange chromatography on DEAE-cellulose and QAE-Sephadex A-50 columns, chromatofocusing, and hydrophobic interaction chromatography on a phenyl-Sepharose CL-4B column. The purified inhibitor was shown to be a dimer of identical subunits and each subunit has a molecular weight of about 34,000. This inhibitor was remarkably thermo- and acid-stable. It was specific for calcium-activated neutral protease and had no effect on any other protease examined (trypsin, papain, alpha-chymotrypsin, bromelain, etc.). It is demonstrated that the inhibition is due to the formation of stoichiometric complex between two enzyme molecules and one inhibitor molecule.
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PMID:Purification and characterization of an inhibitor of calcium-activated neutral protease from rabbit skeletal muscle. 627 75