Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Carp muscle trypsin inhibitor showed an inhibitory effect on bovine trypsin, bovine alpha-chymotrypsin and porcine elastase in a non-competitive, competitive and competitive manner, respectively. The inhibitor formed a stable complex with the above proteinases which was not dissociated in the presence of 2-mercaptoethanol and SDS. The true target proteinase for carp muscle trypsin inhibitor, as yet unknown, seems to be an alpha-chymotrypsin- or elastase-like enzyme rather than trypsin, judging from the manner of inhibition.
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PMID:Inhibitory effect of carp muscle trypsin inhibitor on mammalian pancreatic proteinases. 363 76

A relatively simple procedure for isolation and purification of human blood plasma kallikrein (HPK) by QAE-Sephadex A-50 SP-Sephadex C-50 and affinity chromatography on Sepharose 4B with immobilized soybean trypsin inhibitor with the activity yield of about 40% has been developed. The method allows for simultaneous isolation of low (LMW) and high molecular weight (HMW) kininogens from the same HPK sample. HPK preparations are homogeneous upon 7.5% polyacrylamide gel electrophoresis in the presence of 0.1% SDS; its Mr is 90,000. After treatment with beta-mercaptoethanol, HPK dissociates into two fragments with Mr of 43,000 and 37,000. HPK preparations have high specific activities of esterase (31 microM/min), amidase (78 microM/min), and kininogenase (420 micrograms equiv. bradikinin/min). The high degree of protein purification was demonstrated by titration of active centers with 4-methylumbelliferylguanidine benzoate. The values of equilibrium dissociation constants for the HPK complex with aprotinin (Ki) equal to 1 X 10(-8) M (ethyl ester of N-alpha-benzoyl-L-arginine) and 1,5 X 10(-9) M (HMW) were determined. The kinetics of HPK-induced liberation of bradikinin from purified preparations of HMW and LMW was studied. The kinetic parameters (Km, kcat and kcat/Km) of this reaction suggest a high affinity of HPK for HMW, but not for LMW. LMW does not compete with HMW for the enzyme active center. It is assumed that LMW is not a physiological substrate for HPK.
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PMID:[Various properties and kinetics of interaction of high and low molecular weight human kininogens with human plasma kallikrein]. 363 30

The major urinary trypsin inhibitor UTI I is a proteoglycan. UTI c (Mr 26,000), produced by chrondroitin lyase digestion of UTI I, was isolated and characterized. About 90% of the glycosaminoglycan chain was removed by this treatment without proteolytic modification, as assessed by amino-acid composition and N-terminal sequence of UTI c. Its electrophoretic mobilities on alkaline and SDS-PAGE are identical with those of UTI II which occurs in urine during storage. To study the role of the glycosaminoglycan chain on the inhibitory properties of UTI I, UTI I and UTI c were compared using different proteinases as target enzymes. The inhibitory activity towards bovine trypsin and chymotrypsin as well as human granulocytic cathepsin G did not differ significantly. However, towards human granulocytic elastase, the equilibrium dissociation constant (Ki) is 5 times higher for UTI c than for UTI I. Weak inhibitory activities were measured on human plasmin, UTI c being more efficient than UTI I. The acid-stability of UTI I is not modified after chrondroitin lyase treatment. UTI I and UTI c are equally sensitive to trypsinolysis indicating that the covalently bound glycosaminoglycan chain does not play an important role for the stability of UTI I.
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PMID:The effect of the glycosaminoglycan chain removal on some properties of the human urinary trypsin inhibitor. 364 44

Rabbit polyclonal antibody was raised to a chemically synthesized nonapeptide (Trp-Ala-Glu-Trp-Cys-Gly-Pro-Cys-Lys) corresponding to the active-site sequence of Escherichia coli thioredoxin. The antiserum efficiently inhibited thioredoxin activity in the standard thioredoxin reductase/NADPH coupled assay. This inhibition was blocked by preincubation of the antiserum with the nonapeptide. Tight association of the E. coli thioredoxin to the active-site antibody required SDS denaturation. These results suggest that thioredoxin reductase (NADPH: oxidized-thioredoxin oxidoreductase, EC 1.6.4.5) alters the conformation of thioredoxin sufficiently to permit binding to the antibody. The antiserum bound to plant and liver thioredoxins. Bovine pancreatic trypsin inhibitor, whose active site (Gly-Pro-Cys-Lys) is homologous to that of thioredoxin, also competes for the active-site antibody. This result led to experiments showing that thioredoxin can inhibit the digestion of cytochrome c by trypsin. The ability of thioredoxin to act as a trypsin inhibitor analogue provides a rationale for thioredoxin's resistance to digestion by trypsin.
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PMID:The catalytic active site of thioredoxin: conformation and homology with bovine pancreatic trypsin inhibitor. 370 71

A trypsin inhibitor was purified from carp muscle to apparent homogeneity by the successive chromatographies of DEAE-cellulose, DEAE-Sepharose CL-6B, Con A-Sepharose, Ultrogel AcA 44 and hydroxylapatite. The mol. wt of the inhibitor was estimated to be 58,000 by SDS-polyacrylamide gel electrophoresis or 50,000 by gel filtration. The inhibitor seemed to form a 1:1 stoichiometric complex with trypsin, alpha-chymotrypsin and elastase, respectively. Carp muscle trypsin inhibitor was likely to be identical with serum alpha 1-proteinase inhibitor judging from its glycoprotein nature, mol. wt and the inhibition stoichiometry.
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PMID:Purification and some properties of a trypsin inhibitor from carp (Cyprinus carpio) muscle. 384 14

A protease inhibitor was purified from the African marama bean (Tylosema esculenturm). The inhibitor is present in large amounts, representing about 10.5% of the total protein. The molecular weight is slightly larger than soybean trypsin inhibitor and was estimated at 23,000 by SDS-gel electrophoresis or 24,500 by amino acid analysis. The amino acid composition was atypical of most other plant inhibitors with a cysteine content of only one or possibly two residues/mole and a blocked amino terminus. Inhibition studies indicated virtually no inhibition of chymotrypsin activity. Elastase, however, was inhibited to the same extent as trypsin, requiring about 2 moles of inhibitor for complete inhibition of the enzyme.
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PMID:Isolation and characterization of a proteinase inhibitor from marama beans. 385 Jun 10

A proteolytic activity associated with the microsomal fraction of L-5178Y/Esb tumor cells has been characterized. The enzyme has a molecular weight of 80-90 kD as determined by affinity-labelling with [3H]DFP and SDS-gel electrophoresis. It cleaves ester substrates at the carboxyl position of lysine and arginine and can activate the proenzyme plasminogen. The enzyme is found to be associated with the plasma membranes of high and low metastatic tumor cell lines and is shed in high-molecular-weight form mainly by the high metastatic variant. The pH optimum for esterase and protease activities was 7.5-8.5. Although similar to trypsin in substrate specificity, the enzyme was not inhibited by lima-bean trypsin inhibitor but was inhibited by DFP, PMSF, aprotinin and leupeptin. Partially purified preparations of the protease can alone degrade 125I-labelled endothelial cell extracellular matrix, pointing at the putative role of this enzyme in tumor invasion.
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PMID:Characterization of an extracellular matrix-degrading protease derived from a highly metastatic tumor cell line. 389 58

A purified preparation of trypsin inhibitor was obtained from the hemolymph of a solitary ascidian, Halocynthia roretzi, by a procedure including trypsin-Sepharose chromatography, DEAE-cellulose chromatography, and Sephadex G-50 gel filtration. The product was a mixture of two isoinhibitors, inhibitors I and II. They were separated from each other by high-performance liquid chromatography on an anion exchanger column, and showed almost identical amino acid compositions. They were also indistinguishable in terms of apparent specific inhibitory activity against bovine trypsin when the activity was assayed with the inhibitors at rather high concentrations (greater than 50 nM). A large difference was observed between them, however, in the inhibition constants, which correspond to the dissociation constants of the inhibitor-trypsin complexes; the inhibition constant of inhibitor I was 90 pM, whereas that of inhibitor II was 4.7 nM. The molecular weights of inhibitors I and II were estimated to be 6,000 and 4,500, respectively, by SDS-polyacrylamide gel electrophoresis, while an almost identical value, 9,000, was obtained for both of them by gel filtration. The molecular weight calculated from the amino acid compositions was 5,929 for both. The isoelectric points were also identical, that is about 5.0. Both of the inhibitors were heat-stable. Ascidian inhibitor I also inhibited other trypsin-like enzymes of mammalian origin, as well as those of ascidian origin.
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PMID:Trypsin inhibitor in the hemolymph of a solitary ascidian, Halocynthia roretzi. Purification and characterization. 403 Jul 42

The primary observation, from our laboratory and others, of the effect of blocking the lysyl amino groups of enzymes is the reduction in the fraction of complexes that are resistant to SDS. The blocked enzyme derivatives do cause the specific proteolysis of the alpha 2M subunit to the 85K/100K fragments, and do cause the appearance of new thiol groups. With respect to the sequence of reaction, we may summarize the results by saying that if the reversible DMM-trypsin is, in fact, a model for the native enzyme, proteolysis can precede formation of the presumed covalent bond between bound enzyme and inhibitor. If our preliminary observations are borne out by later experiments, thiol release may precede covalent bond formation or loss of reactivity with amines, suggesting that an intact thiolester need not be the immediate target for amines; another intermediate, possibly the internal pyroglutamate originally proposed by Howard et al. and seen in model studies, may be an additional, or even the primary, target for covalent bonding with native enzymes. With regard to the "trap" hypothesis, the limited release of thiols in a slow phase is suggestive of enzyme activity within the alpha 2M-protease complex, consistent with the theory. Noncovalent irreversible complexes, however, are not a necessary part of associations seen with lysyl-blocked enzymes (which do cause proteolysis and do release thiols); this result is supported by limited data with noncovalently bound native enzymes. Some fraction of irreversible noncovalently bound enzymes may occur, but our results suggest that although alpha 2M-bound enzymes are unusually sterically hindered, the transformation to the presumed covalent state that appears to depend on intact amino groups, may be sufficient to explain the low dissociation of native enzymes. We feel that more experimental evidence is needed to resolve some of the ambiguities on this question but, we feel the existence of a "trapping" reaction has not been proved. In fact, given the possible existence of equilibria between covalent and noncovalent complexes observed, for example, in soybean trypsin inhibitor, and the very low dissociation constants observed with traditional protein-protein complexes, the question of physically encapsulated structures in alpha 2M may not be resolvable without direct evidence from crystal structures.
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PMID:The role of enzyme lysyl amino groups in the reaction with alpha 2-macroglobulin. 620 94

In the presence of intact Hymenolepis diminuta, trypsin was inactivated; intact worms had no apparent effect on subtilisin, pepsin, or papain. Inactivation of trypsin was demonstrable using azoalbumin as a substrate, but the inactivated enzyme retained full catalytic activity against benzoyl-DL-arginine-p-nitroanilide, p-tosyl-L-arginine methyl ester (low molecular weight synthetic trypsin substrates) and p-nitro-p-guanidinobenzoate (an active site titrant). Inactivation was not reversible under conditions of heating, freezing and thawing, or prolonged dialysis of the enzyme. Analyses of inactivated 3H-trypsin by cationic and SDS-polyacrylamide gel electrophoresis, and gel chromatography failed to indicate the presence of a high molecular weight trypsin inhibitor associated with the inactivated enzyme; no low molecular weight, dissociable inhibitor was demonstrable following thermal denaturation of the inactivated enzyme. Analyses of trypsin after incubation in the presence of pulse-labeled worms also failed to demonstrate the presence of any inhibitor of worm origin associated with the inactivated enzyme. The data suggest that inactivation is the result of a small structural or conformational change in the enzyme molecule, a change which partially (rather than totally) inactivates the enzyme towards protein substrates.
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PMID:Trypsin inactivation by intact Hymenolepis diminuta (Cestoda): some characteristics of the inactivated enzyme. 626 43


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