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)

Lymphocyte-activating factor (LAF) has been shown to be produced by LPS-stimulated human adherent cells (monocytes) and peripheral leukocytes, but many non-macrophage cell lines failed to produce LAF. Other macrophage activators including latex microspheres, antigen-antibody complexes, and barium sulfate induce the production of LAF. There is a delay of 6 hr before significant amounts of LAF activity appear in the supernatant medium and maximum activity is found after 12 to 24 hr. Chromatography of concentrated crude supernatant fractions containing LAF activity on Sephadex G-100 gave two peaks of activity (approximately 85,000 and 13,000 daltons). The latter constitutes the major activity and has been purified at least 500-fold with Sephadex G-100, anion exchange, and adsorption chromatography. Optimal stimulation with LAF induces mitosis in 10% of murine thymocytes. The purified activity is sensitive to chymotrypsin and is not affected by treatment with sodium periodate, sulfhydryl reagents, and phenylmethanesulfonylfluoride. The response of thymocytes to LAF decreases with age after 10 weeks and thymocytes obtained from animals injected with cortisone or tumor-bearing animals have an increased responsiveness to LAF.
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PMID:Purification and properties of human lymphocyte activating factor (LAF). 30 Jul 51

An alpha-chymotrypsin-like enzyme was isolated from mast cells of the rat peritoneal cavity by extraction with 0.8 M potassium phosphate, 2 per cent protamine sulfate followed by affinity chromatography on hen ovoinhibitor-agarose and adsorption on barium sulfate. This procedure yielded over 9 mg of protease from the peritoneal lavage fluid of 100 rats, equivalent to 44 per cent of the initial activity. The purified protein was homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, analytical isoelectric focusing, and amino-terminal sequence analysis. The protease contains no covalently bound carbohydrate and has a molecular weight of approximately 26,000. The enzyme molecule is a single polypeptide chain with an amino-terminal sequence homologous to that of the B chain of bovine alpha-chymotrypsin. The kinetic parameters, Km and kcat, for the hydrolysis of N-benzoyl-L-tyrosine ethyl ester were determined at pH 8.0 and 25 degrees C as 1.1 X 10(-3) M and 84 sec-1, respectively. The value of the second-order rate constant for inactivation of mast cell protease by diisopropylphosphofluoridate was 300 times lower than for bovine alpha-chymotrypsin.
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PMID:Purification and partial characterization of an alpha-chymotrypsin-like protease of rat peritoneal mast cells. 49 54

Bovine plasma factor V has been isolated by a preparative procedure involving barium sulfate adsorption, QAEC extraction, poly(ethylene glycol) precipitation, and finally chromatography on a desulfated Sepharose 6B column. Factor V was recovered as a single peak in yields of 35-40% with a specific activity of 50-70 representing a purification of 1000-2000-fold relative to the starting plasma. The apparent molecular weight of the purified factor V was 439,000 +/- 5000. On sodium dodecyl sulfate gel and analytical gel electrophoresis, this factor V preparation showed multiple bands, but results are inconclusive with regard to a possible subunit structure for this factor. The purified factor V was stable for at least 1-2 weeks when stored at 4 degrees C in 0.2 M Tris-acetate, 50 mM CaCl2, 10% glycerol, pH 7.5. When stored at -20 degrees C in 50% glycerol, this preparation was stable for several months. Treatment of the purified factor V with bovine factor Xa, RVV-V, thrombin, or chymotrypsin (but not trypsin) led to a seven- to ten-fold increase in clotting activity and a concomitant decrease in apparent molecular weight. The latter was comparable for each activation system yielding the following average molecular weight values: factor VaSa, 246,000-, factor Va RVV-V, 251,500; Factor Vathr, 239,000; alpha-chymotrypsin, but not trypsin, can activate plasma factor V yielding a product similar to that observed with the above activators. The molar quantities of each of the activators required varied considerably with thrombin having the highest specific activity and factor Xa the lowest. Activation by factor Xa was greatly facilitated by the addition of phospholipid. In the presence of a mixture of phosphatidylcholine/phosphatidylserine (1:1, w/w), the activation of factor V by factor Xa plus Ca2+ required one-third the amount of factor Xa protein as that required in the absence of phospholipid. Even though each of these activators appears to act in an enzymatic manner, the chemical nature of the conversion is unknown at this time.
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PMID:The activation of factor V by factor Xa or alpha-chymotrypsin and comparison with thrombin and RVV-V action. An improved factor V isolation procedure. 126 97

Several murine monoclonal anti-human Factor VII antibodies were produced using hybridoma technology. Two noncompetitive monoclonal antibodies were used to examine by Western blotting the Factor VII cross-reactive material (CRM) in normal human plasma and three commercially available congenitally Factor VII-deficient plasmas, and to construct a facile "sandwich" immunoassay for plasma Factor VII. A second, previously undescribed, form of Factor VII CRM was detected in human plasma, which on Western blotting stained with an apparent intensity 5-8% that of Factor VII. This glycoprotein, tentatively called VII*, has a molecular weight 4,500 D less than Factor VII, lacks detectable Factor VII functional activity, does not bind to barium citrate, and is not recognized by a monoclonal antibody that recognizes Factor VII but not alpha-chymotrypsin-treated Factor VII. VII* was not proteolytically produced from Factor VII during in vitro coagulation or after infusion of human Factor VII into rabbits. As determined by Western blotting, the human hepatoma cell line, HepG2, cultured in the presence of vitamin K, secreted relatively greater levels of VII* in proportion to VII (75%) than that found in human plasma. Warfarin treatment of HepG2 cells decreased the quantity of VII secreted by 77%, whereas it only inhibited the secretion of VII* by 14%. Immunologic studies of the plasmas from a patient on chronic warfarin therapy and an individual given a short course of high dose warfarin therapy corroborated the in vitro synthetic studies obtained with HepG2 cells. The data are consistent with the production of VII* by posttranslational, proteolytic, modification of VII, that, at least in the HepG2 cells studied, occurs intracellularly. However, other mechanisms for the production of VII*, in particular, alternative RNA splicing of the transcript from a single gene, cannot be excluded.
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PMID:Monoclonal anti-human factor VII antibodies. Detection in plasma of a second protein antigenically and genetically related to factor VII. 299 51

Although most L-type calcium channel alpha(1C) subunits isolated from heart or brain are approximately 190-kDa proteins that lack approximately 50 kDa of the C terminus, the C-terminal domain is present in intact cells. To test the hypothesis that the C terminus is processed but remains functionally associated with the channels, expressed, full-length alpha(1C) subunits were cleaved in vitro by chymotrypsin to generate a 190-kDa C-terminal truncated protein and C-terminal fragments of 30-56 kDa. These hydrophilic C-terminal fragments remained membrane-associated. A C-terminal proline-rich domain (PRD) was identified as the mediator of membrane association. The alpha(1C) PRD bound to SH3 domains in Src, Lyn, Hck, and the channel beta(2) subunit. Mutant alpha(1C) subunits lacking either approximately 50 kDa of the C terminus or the PRD produced increased barium currents through the channels, demonstrating that these domains participate in the previously described (Wei, X., Neely, a., Lacerda, A. E. Olcese, r., Stefani, E., Perez-Reyes, E., and Birnbaumer, L. (1994) J. Biol. Chem. 269, 1635-1640) inhibition of channel function by the C terminus.
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PMID:Proteolytic processing of the C terminus of the alpha(1C) subunit of L-type calcium channels and the role of a proline-rich domain in membrane tethering of proteolytic fragments. 1072 94