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)

It was shown on Wistar rats that trypsin and kallikrein decrease the activity of lactate dehydrogenase, alpha-glycerophosphate dehydrogenase, glycogen content and increase the activity of succinate dehydrogenase in neutrophils.
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PMID:[Effect of trypsin, kallikrein and kontrikal on the enzyme activity and cationic protein content of the blood neutrophils]. 242 65

Endothelial injury has been proposed as a feature of a wide variety of vascular diseases, and release of endothelial lysosomal hydrolases could contribute to the pathological changes seen. We have determined the relative activities of 14 glycosidases, two esterases and four peptide hydrolases in human umbilical vein endothelial cells and investigated whether known agonists of endothelial function, or materials known to modulate hydrolase secretion in other phagocytic cells, influenced the activity or secretion of these enzymes by human umbilical vein endothelial cells. Hexosaminidase, beta-galactosidase, beta-glucuronidase and alpha-iduronidase accounted for most of the measured glycosidase activity. Acid phosphatase activity greatly exceeded arylsulphatase activity, and most of the measured peptidase activity was due to acid peptidases. Optimum pH and apparent Km values were determined for the most abundant hydrolases. Exposure of human umbilical vein endothelial cells to bradykinin, thrombin or interleukin-1 resulted in negligible release of either hexosaminidase or lactate dehydrogenase (LDH), in contrast to phorbol myristate acetate, which caused a parallel, dose-dependent release of both enzymes. Treatment of these cells with calcium ionophore A23187, trypsin or platelet-activating factor, caused less than 10% release of either hexosaminidase or LDH. Agents known to modulate lysosomal enzyme secretion by other phagocytic cells failed to induce selective secretion of lysosomal enzymes by human umbilical vein endothelial cells.
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PMID:Lysosomal hydrolases of human vascular cells: response to agonists of endothelial function. 264 39

The human HSP70 gene was modified in vitro using oligonucleotide-directed mutagenesis to add sequences encoding a peptide from the testis-specific form of human lactate dehydrogenase (LDH) to the carboxy terminus of HSP70. The peptide-tagged HSP70 can be distinguished from the endogenous HSP70 protein using an LDH peptide-specific antiserum in indirect immunofluorescence assays of cells transiently transfected with an expression vector containing the tagged HSP70 gene regulated by the human HSP70 promoter. A series of deletion mutants within the HSP70 protein coding region were generated. Using double-label indirect immunofluorescence with the LDH peptide-specific antiserum and HSP70-specific mAbs, we compared the intracellular distribution of the deletion mutants to that of endogenous HSP70. We have determined that sequences in the carboxy terminus of HSP70 are necessary for proper nucleolar localization after heat shock. In contrast, sequences in the amino terminus of HSP70 are responsible for the ATP-binding ability of the protein. Mutants that were unable to bind ATP, however, still displayed nucleolar association, indicating that ATP binding is apparently not required for interaction with substrate. Additional support that HSP70 appears to be composed of at least two domains follows from the results of trypsin digestions of wild type and mutant HSP70. Protease digestion of the mutant HSP70 proteins identified a region of HSP70 that, when deleted, affected HSP70 conformation.
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PMID:Mutational analysis of the human HSP70 protein: distinct domains for nucleolar localization and adenosine triphosphate binding. 268 Dec 24

Dibutylcyclic AMP (DiBucAMP) can induce astroblast-containing cultures to form cells which resemble reactive astrocytes observed in vivo. In the present study, myelin- or axolemmal-enriched fractions were assessed for the ability to inhibit (DiBucAMP)-stimulated reactive-like changes in astrocytic cultures. Addition of exogenous myelin- or axolemmal-enriched fractions to DiBcAMP-exposed cultures prevented drug-induced elevation of lactic dehydrogenase (LDH) 2 days after initial addition of the drug and moderated DiBucAMP-induced decreases in the enzyme's activity normally observed 5 days later. The proportion of reactive colonies (i.e., those in which more than 50% of cells are stellate-shape) was significantly lower in cultures exposed to the drug plus myelin or axolemma vs those exposed to DiBucAMP alone. The inhibitory factors in axolemmal fractions were heat sensitive (at 100 degrees C), whereas those in myelin were not. Both fractions were inactivated by trypsin. Whole brain homogenates had no effect on diBucAMP-stimulated changes in culture.
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PMID:Experimental inhibition of reactive gliotic-like changes in astrocytic cultures. 283 12

Modifications induced by dibutyryl cyclic AMP (diBcAMP) and hydrocortisone in the energy metabolism of chick astroblasts in culture have been investigated. DiBcAMP does not modify the levels of enolase, malate dehydrogenase (MDH), total lactate dehydrogenase (LDH) and glutamine synthetase (GS) activities in these cultured glial cells. However, these cells can be sensitized to the nucleotide analog by trypsinization before seeding. The phenomenon affects specifically GS activity and the synthesis, with an inhibitory effect, of the H subunit of LDH. Addition of hydrocortisone to the culture medium stimulates MDH and GS activities of the cells; trypsinization accentuates the stimulatory effect on GS. This hormone also modifies the synthesis of H and M subunits of LDH in a positive and negative way respectively. The phenomenon is increased by trypsin treatment. The present studies indicate clearly that hydrocortisone generates in cultured chick glial cells metabolic modifications qualitatively different from those obtained by diBcAMP. It is suggested that trypsin treatment, by altering some protein constituents of the cell surface, modifies the adhesiveness of different cell types present in the cell suspension after dissociation of the brain and thus leads to select, in culture, a specific astroglial subpopulation.
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PMID:Glutamine synthetase and energy metabolism enzymes in cultured chick glial cells: modulation by dibutyryl cyclic AMP, hydrocortisone, and trypsinization. 285 35

The effects of t-butylhydroperoxide (tBHP), its alkoxyl radical (tBuO.) and its peroxyl radical (tBuOO.) in model systems and on red blood cells were studied. Glyceraldehyde-3-phosphate dehydrogenase was strongly inhibited by tBHP via a direct reaction of the hydroperoxide with an essential sulfhydryl group in the enzyme molecule. Several other enzymes were unaffected by tBHP. Alcohol dehydrogenase was strongly inhibited by tBuO. but was much less sensitive to tBuOO.. Lysozyme, lactate dehydrogenase and trypsin, on the other hand, were very sensitive to the peroxyl and not, or much less, to the alkoxyl radical, whereas acetylcholinesterase was very sensitive to both radicals. tBuOO. caused covalent binding of tryptophan, tyrosine, histidine and methionine to serum albumin. The corresponding alkoxyl radical was ineffective in this respect. Conversely, tBuO. caused peroxidation of linolenic acid, whereas tBuOO. did not. Incubation of human erythrocytes with tBHP caused lipid peroxidation and K+ leakage. Both effects were caused by tBHP-derived radicals generated in a reaction of the hydroperoxide with hemoglobin. With radical scavengers it was possible to dissociate tBHP-induced lipid peroxidation and K+ leakage, demonstrating that these two processes are not causally related. Experimental results indicate that tBuO. causes lipid peroxidation, whereas tBuOO. is responsible for K+ leakage.
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PMID:Inhibition of enzymes and oxidative damage of red blood cells induced by t-butylhydroperoxide-derived radicals. 293 Jul 85

Sonication of a crude rat liver membrane preparation and centrifugation at 100,000 X g yielded a supernatant which activated basal and hormone-sensitive adenylate cyclases [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1]. The membrane origin of the stimulatory activity was confirmed by the use of lactate dehydrogenase as a marker for contamination by cytosol. The solubility of the activating factors was verified by their passage through 0.05 micron diameter pores of Millipore filters. The membrane-derived activators were nondialyzable and destroyed by heat and trypsin in the same manner as adenylate cyclase activators detectable in cytosol. Stimulation by factors from membranes and cytosol was not additive. The amount of the activators which could be freed from membranes by sonication was 12-15% of that contained in cytosol previously separated from the membranes. Soluble activators from the two sources had limited ability to restore adenylate cyclase activity to membranes from the cyclone of S49 mouse lymphoma cells which are deficient in the enzyme's guanine nucleotide-binding stimulatory protein, Ns. Cytosol did not contain a substrate for ADP-ribosylation by cholera toxin that corresponded electrophoretically to Ns. Furthermore, purified Ns did not affect adenylate cyclase activity in preparations stimulated by the soluble activators. These findings suggest that the activating factors found in cytosol may be released from membranes during tissue homogenization. Because these protein activators can be obtained from membranes without use of detergents and can neither substitute for nor be substituted for by Ns in functional assays, they are distinct from Ns.
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PMID:Membrane association of soluble protein activators of rat liver adenylate cyclase. Evidence for distinctness from the guanine nucleotide-binding stimulating protein (Ns). 309 5

Double staining and labeling procedures were employed to simultaneously identify IA+ cells and cells permissive for the replication of the lactate dehydrogenase-elevating virus (LDV) in populations of peritoneal and spleen macrophages from BALB/c and CBA/J mice. No correlation between the expression of IA antigen and LDV permissiveness was observed. Only a low proportion of resident peritoneal macrophages expressed IA antigen and the antigen was lost within 1-2 days in culture whether or not L cell-conditioned medium was present, whereas the cells retained undiminished LDV permissiveness for 4 days and longer. Induction of IA expression on macrophages by injection of mice with concanavalin A, starch or indomethacin (up to 50% of the total macrophages became IA+), or elimination of IA+ macrophages by treatment with anti-IA monoclonal antibodies plus complement had little or no effect on the ability of the cells to support LDV replication in vivo or in vitro. LDV infection of untreated or concanavalin A-treated or starch-treated mice caused a drastic decline in IA+ peritoneal macrophages within 1 day, but the number of IA+ macrophages returned to pre-infection levels by 7 days post-infection without rendering the cells LDV permissive. Treatment of macrophages with trypsin destroyed the LDV receptor on macrophages with minimal loss of IA antigen from the cells. We conclude that the IA antigen is not the major receptor for infection of macrophages from BALB/c or CBA mice by LDV.
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PMID:The IA antigen is not the major receptor for lactate dehydrogenase-elevating virus on macrophages from CBA and BALB/c mice. 316 28

Children suffering from chronic renal insufficiency frequently show a liver cell damage. It is not clarified, whether this damage is caused immediately by chronic renal insufficiency. In the model of fetal rat hepatocytes, which were isolated by trypsin digestion, we have investigated the influence of normal and uremic serum on the lactate dehydrogenase release and the staining with trypan blue, respectively. Fetal rat hepatocytes under incubation conditions seems to be a useful model in the investigation of the influence of uremic metabolism on the liver cell. In our liver cell model the uremic serum did not influence the membrane permeability of hepatocytes for macromolecules. However, the viability of hepatocytes was impaired by 23% compared with normal serum. The vitality-reducing factor of the uremic serum is not dialysable.
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PMID:[Effect of human uremic serum on the survival of fetal rat hepatocytes]. 323 82

Isolated pancreatic acini from streptozocin-induced diabetic rats were used to study the role of insulin on the synthesis of specific cellular proteins. When acini were incubated with 0-100 nM insulin for 2 h and then pulsed with [35S]methionine, a dose-dependent increase in [35S]methionine incorporation into total cellular proteins was observed. When acinar cell lysates were subjected to gel electrophoresis, 12 major newly synthesized protein bands were resolved. Insulin (100 nM) increased the incorporation of [35S]methionine into all bands but with significantly different rates, varying from 84 to 216% of control. Next, specific antibodies to amylase, trypsin, ribonuclease, myosin, and lactate dehydrogenase (LDH) were used to evaluate the biosynthesis of known proteins. Insulin stimulated labeled amino acid incorporation into amylase by 148% over control. Insulin stimulated the synthesis of trypsinogen to a similar degree, but ribonuclease synthesis showed a significantly smaller increase of 53% over control. Insulin stimulated myosin and LDH synthesis by 169 and 184%, respectively. A differential pattern of protein synthesis was also observed when acini were treated with two other stimulators of protein synthesis, cholecystokinin and hemin. Both of these stimulators had a reduced effect on ribonuclease synthesis compared with amylase and trypsinogen synthesis but failed to increase myosin synthesis. When the RNAs extracted from control acini and acini treated with 100 nM insulin were translated in vitro, the proteins synthesized were quantitatively similar. This study therefore indicates that insulin has translational effects on acinar protein synthesis, and these effects are nonparallel for various specific acinar cell proteins.
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PMID:Insulin and other stimulants have nonparallel translational effects on protein synthesis. 330 74


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