Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By using trypsin-treated human type O cells as indicators, we compared the abilities of four polyanion-divalent cation combinations (heparin-MnCl(2); high-and low-molecular-weight dextran sulfate-CaCl(2); and sodium polyanetholesulfonate [SPS]-CaCl(2)) for removal of serum non-immunoglobulin (lipoprotein) inhibitors of rubella hemagglutination. The combination of SPS-CaCl(2) was found to be the most effective, precipitating completely the pre-beta and beta-lipoproteins and reducing the alpha-lipoprotein levels by more than 50%. Hemagglutination patterns after this treatment were clear and stable, and, when normal sera were tested, hemagglutination-inhibition (HI) titers were comparable to those obtained after standard heparin-MnCl(2) treatment. High-molecular-weight dextran sulfate-CaCl(2) removed serum lipoproteins almost as effectively as SPS-CaCl(2). However, problems of nonspecific agglutination and the heavy hemagglutination patterns resulting made this combination unacceptable for routine purposes. Neither low-molecular-weight dextran sulfate-CaCl(2) nor heparin-MnCl(2) removed the pre-beta lipoproteins completely, and occasionally traces of beta-lipoprotein also remained after treatment. The presence of pre-beta lipoproteins in normal sera after treatment may be of no consequence in the HI test since we have found that the very-low-density lipoprotein fractions obtained by ultracentrifugal methods from normal sera (those corresponding to the pre-beta fractions obtained by electrophoresis) had no HI activity. However, very-low-density lipoprotein fractions from all hyperlipemic sera tested had HI activity (titers ranging from 1:16 to 1:1,024) which, in the majority of cases, was not eliminated after heparin-MnCl(2) treatment. In every case, treatment with SPS-CaCl(2) removed this nonspecific activity completely. Since hyperlipemic sera may occasionally be encountered in routine rubella HI antibody testing, we recommend the use of SPS-CaCl(2) rather than heparin-MnCl(2) for pretreatment of sera.
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PMID:Use of sodium polyanetholesulfonate-CaCl2 for removal of serum nonspecific inhibitors of rubella hemagglutination: comparison with other polyanion-divalent cation combinations. 19 14

Two types of ascites hepatoma cells, AH 66 and AH 130 FN, were treated with trypsin to observe the release of complex carbohydrates constituting the plasma membranes. From AH 66 cells, mucopolysaccharide (heparan sulfate) was preferentially released. From AH 130 FN cells, N-glycosidic glycopeptides were preferentially released whereas no mucopolysaccharide (chondroitin sulfate A) was released.
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PMID:Release of glycopeptides and mucopolysaccharides from ascites hepatoma cells by tryptic treatment. 20 77

Polyoma virus complementary RNA, synthesized in vitro by using highly purified Escherichia coli RNA polymerase and nondefective form I polyoma DNA, was translated in a wheat germ cell-free system. Polypeptides were synthesized that comigrated on sodium dodecyl sulfate-polyacrylamide gels with the polyoma capsid proteins VP1 and VP2, although most of the cell-free products were of smaller molecular weights. The VP1-size protein specifically immunoprecipitated with anti-polyoma virus serum, and upon digestion by trypsin yielded [35S]methionine-labeled tryptic peptides that co-chromatographed with the [3H]methionine-labeled tryptic peptides of virion-derived VP1 on both cation-exchange and anion-exchange resins. The VP2-size in vitro product contained all the virion VP2 methionine-labeled tryptic peptides, as shown by cation- and anion-exchange chromatography and two-dimensional fingerprinting on cellulose. We conclude that full-length polyoma VP1 and VP2 are synthesized in response to complementary RNA and consequently that the viral capsid proteins VP1, VP2, and VP3 are entirely virus coded.
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PMID:Polyoma virus complementary RNA directs the in vitro synthesis of capsid proteins VP1 and VP2. 20 20

A genetically conditioned mouse model of exocrine pancreatic insufficiency (epi) has been used to study the effect of the absence of lumenal proteases on small intestinal mucosal proteins. The small bowel was divided into eight equal segments. Enzyme activity was increased only in the first three segments in the case of maltase, sucrase, and lactase (all mol wt above 200,000). Alkaline phosphatase (mol wt 145,000), trehalase (mol wt 95,000), and peptidase (mol wt 175,000) activities were unaffected in proximal segments from epi mice. Proximal brush border proteins were identified and measured quantitatively by sodium dodecyl sulfate acrylamide gel electrophoresis. Those enzymes with increased activity were associated with increased amounts of protein in epi mice. Double labeled studies of protein turnover revealed a longer half-life for large brush border proteins (mol wt above 175,000) in epi mice than in normal mice. Enterokinase activity (a marker for duodenal mucosa) was nearly absent from the duodenum of epi mice. Receptors for the intrinsic factor-vitamin B12 complex (markers for ileal mucosal) were present in the ileum equally in normal and in epi mice. Enterokinase activity can be induced in epi mice by feeding its substrate trypsinogen, but not by trypsin or chymotrypsinogen. Epi mice thus retain the ability to synthesize enterokinase. Pancreatic proteases play an important role in the turnover of certain large mucosal proteins and in the induction of enterokinase.
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PMID:Effect of exchange exocrine pancreatic insufficiency on small intestine in the mouse. 20 83

The membrane receptor for epidermal growth factor (EGF) on 3T3 cells has been identified and specifically labeled radiochemically using a photoreactive derivative of EGF. Photoreactive EGF, labeled with 125I, was incubated with 3T3 cells and then photolyzed in situ to generate a nitrene capable of reacting with a wide variety of chemical bonds. Analysis of the system by sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed, besides the band of EGF, only 1 other major radioactive band which migrated at approximately 190,000 daltons. This band was absent when a nonresponsive and nonbinding variant of 3T3 was used. A direct proportionality between binding activity and crosslinked complex formation was demonstrated using a variety of binding conditions. The crosslinked complex in intact cells is accessible to the action of a macromolecule like trypsin at 4 degrees, suggesting a cell surface location for this complex. Upon incubation of cells at 37 degrees, radioactivity from previously formed EGF-receptor crosslinked complex is converted by cellular action to 3 forms of mol wt less than or equal to 58,000 daltons. These are not accessible to trypsin action upon intact cells.
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PMID:Affinity labeling of a cell surface receptor for epidermal growth factor. 20 89

A protein, present in bovine seminal plasma, initiates forward motility in immature, immotile caput spermatozoa that have been incubated with a cyclic AMP phosphodiesterase inhibitor. An improved motility assay was developed to study this process and the protein involved. This forward motility protein exhibits multiple forms when fractionated on the basis of charge or molecular weight. Molecular sieving in urea or sodium dodecyl sulfate and dithiothreitol results in a single peak of activity which will re-form the larger aggregates in the absence of these agents. The molecular weight of this monomeric motility protein, as estimated from molecular sieving under these dissociating conditions, is 37,500. The forward motility protein can be partially purified by heat treatment, gell chromatography in urea, and affinity chromatography on concanavalin A/agarose. Enzymatic treatments further suggest a glycoprotein nature, i.e. treatment with beta-galactosidase, neuraminidase, alpha-mannosidase, or galactose oxidase reduces its activity by 50%; treatment with trypsin completely abolishes forward motility protein activity. On the basis of concurrent studies on the activity, properties, and distribution of forward motility protein in bovine body fluids, it is suggested that this protein is involved in the development of the capacity for motility as sperm traverse the epididymis.
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PMID:Bovine sperm forward motility protein. Partial purification and characterization. 21 Nov 30

Protein composition of cardiac sarcolemmal membranes was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Membranes were observed to contain about 20 polypeptide bands ranging from 18000 to 200 000 dalton mass. Out of these, six bands were prominent and together comprised 57% of the membrane protein. When sarcolemmal membranes, phosphorylated by [gamma-(32)P] ATP in the presence of Ca(2+) or Na+ with and without K+, were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis at pH 2.4, the band III region (Mr 105 000) of gels was found to contain active sites of monomeric Ca-ATPase and (Na,K)ATPase. Bands I (Mr greater than 200 000), II (Mr 150 000), III (Mr 105 000), and VI (Mr 47 000) were accesible to trypsin; the extent of proteolysis was dependent on the time of exposure to, and the concentration of, trypsin (i.e, ratio of sarcolemmal protein/trypsin). Addition of molar sucrose protected sarcolemmal proteins from the tryptic proteolysis. Calcium transport was reduced by the action of trypsin; the degree of reduction was influenced by the time of exposure of membranes to trypsin as well as the concentration of trypsin. (Mg,Ca)ATPase activity, on the other hand, was elevated moderately at lower concentration and reduced at higher concentration of trypsin. Treatment with phospholipase C cium transport and (Mg,Ca)ATPase activity; electrophoretic patterns were unaffected by this treatment. Addition of lecithin to phospholipase C treated membranes produced a moderate increase in calcium transport. Exposure to Triton X-100 (1%) specifically solubilized three protein bands (Mr90 000, 67 000, and 57 000), whereas exposure to deoxycholate (1%) preferentially solubilized high-molecular-weight proteins, including band III (Mr 105 000); Lubrol-PX (1%) caused nonspecific solubilization of proteins, although the extent of solubilization with Lubrol-PX was considerably less than with either Triton or deoxycholate.
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PMID:Protein analysis of cardiac sarcolemma: effects of membrane-perturbing agents on membrane proteins and calcium transport. 21 4

Acetate kinase (ATP:phosphotransferase E.C.2.7.2.1) has been purified to a high state of purity from Veillonella alcalescens. The native enzyme had a molecular weight of 88,000, as determined by Sephadex G-150 gel filtration. The molecular weight of the monomeric enzyme, estimated from sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was 42,000. The enzyme was determined to be a homodimer from the amino acid composition and the results of trypsin digestion and cyanogen bromide cleavage. Two moles of phosphate were incorporated into the dimer upon incubation of the enzyme with ATP and acetate. These results support the conclusion that each subunit of the dimeric enzyme consists of a single active catalytic center. Succinate enhanced the rate of ATP-ADP phosphoryl group exchange 20-fold and the binding of ATP 10-fold. These results are considered in light of data from previous reports (Pelroy, R. A., and Whiteley, H. R. (1971) J. Bacteriol. 105, 259-267; Bowman, C. M., Valdez, R. O., and Nishimura, J. S. (1976) J. Biol. Chem 251, 3117-3121).
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PMID:Acetate kinase from Veillonella alcalescens. Purification and physical properties. 21 74

Bacteriocins of Clostridium perfringens were prepared by ammonium sulfate precipitation of supernatant broth from 10 bacteriocinogenic strains. These bacteriocins were compared with respect to their ability to produce spheroplasts in a sensitive indicator strain; their inducibility; sensitivity to pH, proteolytic enzymes, and boiling; and their effect on macromolecular synthesis. Two bacteriocins were stable over a wide range of pH values and resisted boiling, and three bacteriocins were resistant to trypsin. Five bacteriocins shut down DNA, RNA, and protein synthesis; three bacteriocins had varying effects on DNA and RNA synthesis; and two bacteriocins had little effect on macromolecular synthesis. Antiserum prepared against one bacteriocin highly neutralized three bacteriocins with partial neutralization of five others; two bacteriocins were unaffected. Mutant strains selected for resistance to bacteriocin 28 also demonstrated coresistance to two other closely related bacteriocins and partial resistance to five others.
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PMID:Comparative study of ten bacteriocins of Clostridium perfringens. 21 2

Resident mouse peritoneal macrophages were shown to take up and degrade acetylated (125)I-labeled low density lipoprotein ((125)I-acetyl-LDL) in vitro at rates that were 20-fold greater than those for the uptake and degradation of (125)I-LDL. The uptake of (125)I-acetyl-LDL and its subsequent degradation in lysosomes were attributable to a high-affinity, trypsin-sensitive, surface binding site that recognized acetyl-LDL but not native LDL. When (125)I-acetyl-LDL was bound to this site at 4 degrees C and the macrophages were subsequently warmed to 37 degrees C, 75% of the cell-bound radioactivity was degraded to mono[(125)I]iodotyrosine within 1 hr. The macrophage binding site also recognized maleylated LDL, maleylated albumin, and two sulfated polysaccharides (fucoidin and dextran sulfate) indicating that negative charges were important in the binding reaction. A similar binding site was present on rat peritoneal macrophages, guinea pig Kupffer cells, and cultured human monocytes but not on human lymphocytes or fibroblasts, mouse L cells or Y-1 adrenal cells, or Chinese hamster ovary cells. Uptake and degradation of acetyl-LDL via this binding site stimulated cholesterol esterification 100-fold and produced a 38-fold increase in the cellular content of cholesterol in mouse peritoneal macrophages. Although the physiologic significance, if any, of this macrophage uptake mechanism is not yet known, we hypothesize that it may mediate the degradation of denatured LDL in the body and thus serve as a "backup" mechanism for the previously described receptor-mediated degradation of native LDL that occurs in parenchymal cells. Such a scavenger pathway might account for the widespread deposition of LDL-derived cholesteryl esters in macrophages of patients with familial hypercholesterolemia in whom the parenchymal cell pathway for LDL degradation is blocked, owing to a genetic deficiency of receptors for native LDL.
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PMID:Binding site on macrophages that mediates uptake and degradation of acetylated low density lipoprotein, producing massive cholesterol deposition. 21 98


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