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)

1. Two forms of fatty acid-binding proteins (FABPs) were isolated from human, pig and rat liver cytosols by gelfiltration and anion-exchange chromatography. 2. Both forms did not show physicochemical or chemical differences. They had an Mr of about 14.5 kDa for all species. pI Values were 5.8 for both forms of human and pig liver FABP and 6.4 for both forms of rat liver FABP. In contrast to heart FABPs no tryptophan was present in liver FABPs. 3. Liver FABPs show a much higher enhancement of fluorescence at binding of 11-dansylaminoundecanoic acid, 16-anthroyloxy-palmitic acid and 1-pyrene-dodecanoic acid than heart FABPs and additionally a blue shift in excitation and emission wavelengths with the first fatty acid. 4. The bulky side-chain did not affect fatty acid binding since binding constants of liver FABPs were comparable for these fluorescent fatty acids and oleic acid (0.3-0.7 microM). 5. A 1:1 binding stoichiometry was obtained for oleic acid binding with heart and liver FABPs. 6. Liver FABPs have a high binding affinity for C16-C22 saturated and unsaturated fatty acids, palmitoyl-CoA, bromo-substituted fatty acids, POCA, tetradecylglycidic acid and flavaspidic acid. 7. Fatty acid binding could be reduced to less than 50% by arginine modification with 2,3-butadione or by enzymatic degradation of FABPs with trypsin or pronase.
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PMID:The binding affinity of fatty acid-binding proteins from human, pig and rat liver for different fluorescent fatty acids and other ligands. 274 9

An alpha-amylase inhibitor was prepared from cranberry bean (Phaseolus vulgaris). The alpha-amylase inhibitor was composed of three different subunits not linked by disulfide bridges and only one of them contained carbohydrate. Although the inhibitor was stable at pH 3 to 7, it was heat labile at pH 3 and 5. Chemical modification of the amino groups and the guanido groups in cranberry bean alpha-amylase inhibitor molecule resulted in rapid loss of the inhibitory activity, respectively. Oxidation of the tryptophan residues also led to loss of the activity. On the other hand, reductive methylation of the amino groups scarcely affected the activity. The inhibitor was quite resistant to the proteolytic digestions by pepsin and trypsin, while it was relatively susceptible to the action of chymotrypsin.
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PMID:Activity changes in cranberry bean (Phaseolus vulgaris) alpha-amylase inhibitor by chemical modification and enzymatic digestion. 278 53

Thrombomodulin, an endothelial cell protein, binds thrombin with high affinity and alters thrombin from a procoagulant to an anticoagulant molecule. In this study, chemical and/or proteolytic modification of thrombin was carried out to identify the essential components required for its interaction with thrombomodulin. Modification of thrombin at the catalytic site serine and histidine residues, with Diisopropylfluorophosphate and Tosyl-L-lysine chloromethyl ketone, resulted in loss of clotting and amidolytic activity. Both Diisopropyl phosphoryl-thrombin and Tosyl-L-chloromethyl ketone-thrombin inhibited native-thrombin: thrombomodulin catalyzed protein C activation with Ki values of 5 nM and 6 nM respectively indicating no loss of affinity for thrombomodulin. Oxidation of tryptophan residues with N-bromosuccinimide or iodination of tyrosine residues of thrombin led to reduced clotting and amidolytic activity as well as a reduced ability to interact with thrombomodulin. Modification of arginine residues with Phenylglyoxal and 2,3,Butanedione led to loss of thrombomodulin binding affinity. Limited proteolysis of thrombin by trypsin yielded the derivative beta-thrombin which had also lost its ability to interact with thrombomodulin. Deglycosylation of thrombin did not alter its binding affinity for thrombomodulin. These results indicate that one or more tryptophan, arginine and tyrosine residues are essential for the recognition of thrombin by thrombomodulin whilst the carbohydrate side chain and the active site residues of the thrombin molecule are not involved in thrombomodulin binding.
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PMID:Modification of human thrombin: effect on thrombomodulin binding. 284 49

A proteinase inhibitor for elastases was isolated from extracts of the sea anemone Anemonia sulcata and purified to apparent homogeneity. The procedure comprises ethanolic extraction of the deep-frozen animals followed by gel filtration on Sephadex G-50 and by ion exchange chromatography on DEAE-Sephadex A-25 and SP-Sephadex C-25 and by hydroxylapatite chromatography. The slightly acidic inhibitor (isoelectric point 5.9) is a small protein consisting of 48 amino-acid residues without tryptophan and phenylalanine. The single chain molecule contains two methionines and no free sulfhydryl group but six cysteines presumably forming disulfide bonds. Reaction with cyanogen bromide abolishes the inhibitory properties. The inhibitor exhibits a rather narrow specificity for elastases. It strongly inhibits porcine pancreatic elastase in a permanent fashion with an equilibrium dissociation constant Ki of about 10(-10)M and somewhat weaker the elastase from human leucocytes with a Ki of about 10(-7)M. No obvious inhibition is observed of other serine proteinase such as bovine trypsin, bovine chymotrypsin, subtilisin from Bacillus subtilis and cathepsin G from human leucocytes when tested with synthetic substrates.
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PMID:A new inhibitor of elastase from the sea anemone (Anemonia sulcata). 288 64

Amino acid sequences of neurotoxins RTX-IV and RTX-V isolated from the sea anemone Radianthus macrodactylus were determined by the automated Edman degradation; their polypeptide chains consist of 48 and 47 amino acid residues, respectively. For identification of tryptophan-30 in toxin RTX-IV, its trypsin and chymotrypsin digests were investigated. Amino acid sequences of the above toxins show that they belong to a new structural class and that C-terminal positive charge and tyrosine-25 are important for toxic activity of sea anemone polypeptides.
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PMID:[Amino acid sequence of neurotoxins IV and V from the sea anemone Radianthus macrodactylus]. 290 96

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

Trypsin was used as a probe of F-actin conformation. F-actin is known to be refractory to proteolysis [Jacobson, G.R. and Rosenbusch, J.P. (1976) Proc. Natl. Acad. Sci. U.S. 73, 2742-2746]. However, here it was found that F-actin could also be digested by trypsin to a 33-kDa fragment (like G-actin) when free MgADP is present in the medium. The amounts of degradation of F-actin depended on the ADP concentration; saturation occurred at about 0.5 mM. Elimination of divalent cations from the medium completely suppressed the effect of ADP on the digestion of F-actin. Other nucleotides were also examined. The effect decreased in the order ADP greater than ATP much greater than IDP greater than GDP = UDP. Adenine, adenosine, AMP, and PPi had no effect at all. epsilon-ADP had the effect, and its fluorescence was changed on the addition of F-actin. The intrinsic tryptophan fluorescence spectrum of F-actin was ADP-dependent. These results suggest the presence of a second nucleotide interacting site on actin and that ADP interaction at this site induces conformational changes in monomeric actin molecule in F-actin filaments.
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PMID:Structural aspects of skeletal muscle F-actin as studied by tryptic digestion: evidence for a second nucleotide interacting site. 297

The phosphoprotein NS of vesicular stomatitis virus which accumulates within the infected cell cytoplasm is phosphorylated at multiple serine and threonine residues (G. M. Clinton and A. S. Huang, Virology 108:510-514, 1981; Hsu et al., J. Virol. 43:104-112, 1982). Using incomplete chemical cleavage at tryptophan residues, we mapped the major phosphorylation sites to the amino-terminal half of the protein. Analysis of phosphate-labeled tryptic peptides suggests that essentially all of the label is within the large trypsin-resistant fragment predicted from the sequence of Gallione et al. (J. Virol. 39:52-529, 1981). A similar result has been obtained for NS protein isolated from the virus particle by C.-H. Hsu and D. W. Kingsbury (J. Biol. Chem., in press). Analysis of phosphodipeptides utilizing the procedures of C. E. Jones and M. O. J. Olson (Int. J. Pept. Protein Res. 16:135-142, 1980) enabled us to detect as many as six distinct phosphate-containing dipeptides. From these studies, together with the known sequence data, we conclude that the major phosphate residues on cytoplasmic NS protein are located in the amino third of the NS molecule and most probably between residues 35 and 106, inclusive. The studies also provide formal chemical proof that NS protein has a structure consistent with a monomer of the sequence of Gallione et al. as modified by J. K. Rose (personal communication). The low electrophoretic mobility of this protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis is not therefore due to dimerization.
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PMID:Phosphorylation sites on phosphoprotein NS of vesicular stomatitis virus. 298 24

Sendai virus-induced hemolysis, a manifestation of virus-red cell fusion, is inhibited by exposure of the virus to 50 microM and higher concentrations of trifluoperazine. Trifluoperazine does not disrupt the virus, since trifluoperazine-treated virus with no hemolytic activity sediments slightly faster than untreated virus on sucrose density gradients and contains viral proteins in proportions characteristic of untreated virus. Trifluoperazine affects the fusion protein to a greater extent than the hemagglutinin, since trifluoperazine-treated virus with no hemolytic activity is as active or nearly as active in agglutinating red cells. The partition coefficient of trifluoperazine between the virus membrane and buffer is lower at 4 degrees C than, but the same at 37 degrees C, as that between the red cell membrane and buffer. Nevertheless, virus-independent red cell lysis and inactivation of virus-mediated hemolysis occur when the red cell and viral membranes, respectively, contain similar concentrations of trifluoperazine. Furthermore, 13-28% more trifluoperazine is necessary to achieve either effect at 4 degrees C or at 25 degrees C than at 37 degrees C. Changes in the surface activity of trifluoperazine do not explain these results, insofar as the critical micellar concentration of (0.75 mM) and maximal reduction in surface tension by (40 dyn/cm) trifluoperazine are the same at 25 degrees C and 37 degrees C. The fluorescence of viral tryptophan decreases by approx. 25% when viral hemolysis is inactivated by trifluoperazine, by trypsin treatment or by heating at 100 degrees C for 5 min.
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PMID:Trifluoperazine inhibits Sendai virus-induced hemolysis. 300 73

The preparation of fluorescence labeled acyl enzymes (Streptomyces griseus trypsin) was successfully carried out using specific trypsin substrates, 'inverse substrates'. The topographical analysis of the structures of the area around the active site was carried out by measuring the fluorescence spectra of the acyl enzyme preparations and these results were compared with those of bovine trypsin. It was found that the polarity of the active site vicinity at pH 5 was similar to that of bovine trypsin, whereas considerable differences were noticed at lower pH as a result of pH-induced transformation. Conformational changes of the active site induced by the interaction with the specific ligand were analyzed from the fluorescence spectra. In these responses the two enzymes were quite distinguishable. The two enzymes active sites were also different in the energy transfer experiments. The spatial arrangements of the catalytic residues relative to the intrinsic tryptophan residues were suggested to be substantially different for the two enzymes.
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PMID:Comparison of Streptomyces griseus and bovine trypsin by active site analysis using fluorescent acyl groups. 310 86


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