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)

Enzymes were deposited on different porous support materials and these preparations were used to catalyze reactions in organic media. Reactions were carried out at specific water activities, achieved by equilibrating both the enzyme preparation and the substrate solution at the desired water activity before mixing them and thereby starting the reactions. The reaction rates obtained at the same water activity with different supports differed greatly, indicating a direct influence of the support on the enzyme. For horse liver alcohol dehydrogenase, Celite was the best support, and the reaction rate increased with increasing water activity. In the alpha-chymotrypsin-catalyzed alcoholysis of N-acetyl-L-phenylalanine ethyl ester with 1-butanol, high rates were again obtained with Celite, but with this support only about one third of the ethyl ester was converted to butyl ester, the rest was hydrolyzed. With the polyamide support, Accurel PA6, alcoholysis was the dominating reaction, and by using a low water activity (0.33), hydrolysis was completely suppressed while still maintaining a high alcoholysis activity. Controlled pore glass (CPG), derivatized with either hexyl or glucosyl groups, had quite different properties as enzyme supports. For horse liver alcohol dehydrogenase, glucose-CPG was a much better support than hexyl-CPG, and in the alpha-chymotrypsin-catalyzed reactions, glucose-CPG favored hydrolysis, and hexyl-CPG alcoholysis, at water activities exceeding 0.8. The results are discussed considering the absorption of water on the enzymes, on the supports and the solubility of water in the reaction media; all these parameters were measured separately.
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PMID:On the importance of the support material for enzymatic synthesis in organic media. Support effects at controlled water activity. 186 47

This investigation sought to characterize biochemically the tumor-specific transplantation antigens (TSTA) expressed on the cell surface of a panel of chemically induced fibrosarcomas of C3H/HeJ mice. Results suggest a uniform antigenic framework upon which individual specificities are superimposed. The antigens expressed by the 3-methylcholanthrene-induced fibrosarcomas MCA-D, MCA-F, and MCA-2A fulfill the requirements of a TSTA; namely, immunization of syngeneic hosts with irradiated cells or soluble extracts engenders a tumor-specific immune response such that animals resist challenge with the same, but not another, tumor. Brief incubation of intact tumor cells in single-phase aqueous solutions of 2.5% (v/v) 1-butanol extracts an immunoprotective TSTA, but not alloantigenic activity, from MCA-F cells. This extraction protocol was extended to the two other MCA-induced neoplasms. The butanol-extracted TSTA from the three tumors displayed isoelectric pHs of 6.4 to 6.6 following preparative isoelectric focusing. The tumor-specific immunoprotective activity from all three tumors displayed an apparent molecular weight of 150,000 (150 kDa) during high-performance gel permeation chromatography. The chromatographic properties of the 150 kDa antigens were unaffected by reduction using dithiothreitol, but incubation in acetate buffer, pH 3.0, dissociated the 150 kDa complex into at least two components with molecular weights of 70 to 100 kDa and 20 to 40 kDa. Only the smaller component displayed TSTA activity. The presence of two major components in the 150-kDa antigen was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. TSTA activity was sensitive to digestion with pronase, papain, chymotrypsin, and alpha-mannosidase, but resistant to DNase, RNase, neuraminidase, trypsin, endoglycosidase H, and a mixed-function glycosidase. In addition, the TSTA activity was unaffected by heating. These data demonstrate that MCA carcinogenesis results in the expression of immunologically unique epitopes on biochemically related glycoproteins and suggest a unified mechanism for the generation of TSTA polymorphism.
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PMID:Biochemical characterization of 1-butanol-extracted murine tumor-specific transplantation antigens. 240 45

1. The results of this study indicates that the binding of insulin to brain plasma membranes activates a membrane protease which, by a trypsin like mechanism, produces a soluble factor that modulates the PDH behaviour when added to brain mitochondria. 2. The supernatant from brain plasma membranes incubated with 0.5 mg/ml trypsin added to mitochondria increases PDH activity levels and cancels PDH inhibition by NaF, as has already been seen when the plasma membranes are incubated with 25 microU/ml insulin. No such effects are obtained when the incubation is run out with 0.5 mg/ml chymotrypsin. 3. The supernatants from insulin or trypsin treated plasma membranes retain their activating properties on mitochondrial PDH also after dansylation; from these preparations a dansylated active on PDH material was separated by monodimensional chromatography on HPTLC silica Gel plates, using chloroform/1-butanol (93:7 v/v) as a solvent. 4. Insulin incubation of plasma membranes pretreated with protease inhibitors (leupeptin, phenylmethylsulfonylfluoride) or with exogenous trypsin, but not chymotrypsin substrates (esters of arginine and tyrosine) yields an inactive supernatant on PDH. 5. Insulin treated plasma membrane supernatants lose all stimulating properties on PDH after incubation for 1 hr with 2 mg/ml trypsin or chymotrypsin.
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PMID:Evidence of an insulin generated pyruvate dehydrogenase stimulating factor in rat brain plasma membranes. 331 49

A quick and simple method has been developed for the recovery of proteins from water-in-oil microemulsions (w/o-MEs), which is needed to further the use of liquid-liquid extraction in bioseparations. By adding a small portion (0.1 v/v or less) of cosurfactant (e.g., 1-alkanol) to w/o-ME solution, proteins were readily expelled, sometimes as solids, while most or all of the surfactant (Aerosol OT) remained in solution. The release of proteins increased with the further addition of cosurfactant and was greater when the molar ratio of protein to w/o-ME or fractional occupancy (f) was high. However, protein expulsion was also significant when f was small. The addition of cosurfactant released ribonuclease, lysozyme, alpha-chymotrypsin, pepsin, bovine serum albumin (BSA), and catalase from w/o-ME solution, but the expulsion was greater for BSA relative to chymotrypsin and lysozyme. Protein expulsion also increased with cosurfactant chain length for the homologous series of 1-alkanols starting at 1-butanol; however, water was also coexpelled in significant amounts. An exception to the latter rule was 1-butanol, which readily promoted the release of protein, but not encapsulated water. The addition of 1-butanol to a w/o-ME solution containing alpha-chymotrypsin and BSA selectively released the former protein, with chymotryptic activity occurring in the recovered protein. Possible mechanisms for the cosurfactant-mediated release of protein are discussed. Copyright 1998 John Wiley & Sons, Inc.
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PMID:Expulsion of proteins from water-in-oil microemulsions by treatment with cosurfactant 1009 72

Activation of zymogens within the pancreatic acinar cell is an early feature of acute pancreatitis. Supraphysiological concentrations of cholecystokinin (CCK) cause zymogen activation and pancreatitis. The effects of the CCK analog, caerulein, and alcohol on trypsin and chymotrypsin activation in isolated pancreatic acini were examined. Caerulein increased markers of zymogen activation in a time- and concentration-dependent manner. Notably, trypsin activity reached a peak value within 30 min, then diminished with time, whereas chymotrypsin activity increased with time. Ethanol (35 mM) sensitized the acinar cells to the effects of caerulein (10(-10) to 10(-7) M) on zymogen activation but had no effect alone. The effects of ethanol were concentration dependent. Alcohols with a chain length of >or=2 also sensitized the acinar cell to caerulein; the most potent was butanol. Branched alcohols (2-propanol and 2-butanol) were less potent than aliphatic alcohols (1-propanol and 1-butanol). The structure of an alcohol is related to its ability to sensitize acinar cells to the effects of caerulein on zymogen activation.
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PMID:Alcohols enhance caerulein-induced zymogen activation in pancreatic acinar cells. 1184