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)

A short digestion with excess of trypsin releases an inhibitor with an apparent molecular weight of 14,000 from both the inter-alpha-trypsin inhibitor and the ITI-related acid-stable inhibitor. The amino acid sequence of this inhibitor was determined. The inhibitor is composed of two covalently linked homologous Kunitz-type domains. One domain has antitryptic activity, as reported. This paper characterizes the second, inactive domain as also of the Kunitz type.
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PMID:Kunitz-type proteinase inhibitors derived by limited proteolysis of the inter-alpha-trypsin inhibitor, II. Characterization of a second inhibitory inactive domain by amino acid sequence determination. 9 48

A trypsin inhibitor was isolated from pregnant mares' urine by adsorption on bentonite and elution with aqueous pyridine followed by batch DEAE-cellulose treatment and column chromatography. Final purification to an electrophoretically homogenous glycoprotein was achieved by gel permeation chromatography. This equine urinary trypsin inhibitor (E-UTI) is acid- and heat-stable, has a molecular weight of 22 to 23 kDa, an isoelectric point of 4.55, forms a 1:1 molar complex with trypsin and has serine as its N-terminal amino acid. The N-terminal amino acid sequence of this protein is almost identical with that of EI-14, the inhibitor obtained from horse serum by tryptic treatment, except for two extra amino acid residues, Ser-Lys- on the N-terminal end of E-UTI. In its isoelectric point E-UTI differs from EI-14 and the inhibitor from human urine.
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PMID:Characterization of a trypsin inhibitor from equine urine. 162 53

The polymorphism of inter-alpha-trypsin-inhibitor, ITI, was demonstrated by isoelectric focusing in agarose gels (pH 5-8) followed by protein blotting and immunoassay. Segregation in 239 families with 677 children is consistent with the formal hypothesis that there are two common codominant alleles, ITI*1, ITI*2, and one rare codominant allele, ITI*3, at an autosomal locus ITI. Allele frequencies were calculated as ITI*1 = 0.600, ITI*2 = 0.393, ITI*3 = 0.007. Linkage analysis with 36 markers is presented. Slightly positive lod scores were obtained for PGM3 (zeta = 1.35, theta = 0.10) and AK1 (zeta = 1.34, theta = 0.10).
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PMID:Genetic polymorphism of inter-alpha-trypsin-inhibitor (ITI): formal genetic and linkage analyses. 170 12

The N-terminal amino-acid sequence of human ITI has been found to be identical with that of the acid-stable human 30-kDa inhibitors (HI-30) from urine, serum, and those released from inter-alpha-trypsin inhibitor by trypsin or chymotrypsin. Serum HI-30 and HI-30 released by trypsin differ from the urinary inhibitor by an additional C-terminal arginine residue. Compared to these two inhibitors the inhibitor released by chymotryptic proteolysis is elongated C-terminally by an additional phenylalanine residue. These results strongly favour HI-30 as the N-terminus of the inter-alpha-trypsin inhibitor and its release from this inhibitor in vivo by cleavage of the Arg123-Phe124 peptide bond by trypsin-like proteinases.
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PMID:Human inter-alpha-trypsin inhibitor: localization of the Kunitz-type domains in the N-terminal part of the molecule and their release by a trypsin-like proteinase. 240 38

SDS-polyacrylamide gel electrophoresis and immunoblot were applied to analysis of plasma proteins immunologically related to inter-alpha-trypsin inhibitor (ITI). In this system, anti-ITI sera were able to identify ITI and other components with an Mr near 120 kDa which would be degradation products of ITI by limited proteolysis. An anti-UTI (urinary trypsin-inhibitor) serum could detect, beside these derivatives, two minor components (Mr values near 90 and 60 kDa). Analysis of perchloric acid supernatants of plasma samples, using the same technic, induced visualization of a new component, similar to urinary trypsin inhibitor which could not be detected by direct analysis. This one was also characterized in a higher content in pathological samples (renal failure and infectious diseases).
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PMID:Plasma proteins immunologically related to inter-alpha-trypsin inhibitor. 245 40

Strong activity of acid-stable trypsin inhibitor (ASTI) was confirmed in some clinical thrombin preparations. Thrombin preparations of human plasma origin had no detectable ASTI activity, whereas some preparations of bovine plasma origin revealed more than 5,000 U/vial (5,000 thrombin units), indicating a higher content of ASTI than of thrombin in terms of protein concentration. Contamination by other biologically active substances was also suggested by variations in amidolytic activity with several synthetic substrates (S-2238, S-2251, S-2444, S-2266 and Bz-L-Arg-pNA). On isoelectric focussing, the ASTI activities migrated in acidic positions with pI values of 3.9, 4.5, 5.0, 5.9 and 6.5, respectively. They were almost parallel to the thrombin Bz-L-Arg-pNA hydrolytic activity, and differed from that of the purified thrombin preparation (pI = 7.0). By gel filtration on Sephadex G-100, the molecular weights of the inhibitors as calculated using standard proteins were 140,000 (main), 70,000 and less than 10,000 (minor), respectively. An immunological difference between the main inhibitor (pI = 3.9, mol wt 140,000) and previously reported plasma ASTI was also confirmed with goat anti-UTI serum by the double immunodiffusion and ELISA methods. The inhibitor exerted a strong inhibitory effect not only on trypsin and chymotrypsin, but also on non-plasmic fibrinolysis with human leukocyte elastase, and to a lesser extent on the blood coagulation system (lengthening of APTT and PT). Clearly, when using thrombin preparations and analyzing the data obtained after their administration, the effects of this and other contaminant biologically active substances must be taken into account.
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PMID:Strong activity of acid-stable trypsin inhibitor in bovine thrombin for clinical use. 314 Oct 90

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

Antisera against purified urinary trypsin inhibitor (UTI-I, molecular weight 67,000) and UTI-III (molecular weight 23,000) were first produced in rabbits. Both anti-UTI-I and anti-UTI-III sera formed a single immunoprecipitin line with human plasma inter-alpha-trypsin inhibitor (I alpha TI), whereas two immunoprecipitin lines were formed with crude urine. It was speculated that both UTI-I and UTI-II might be present in normal human urine. In the present study, the inhibitory effects of anti-UTI sera on UTI activity were examined by three different assay methods. The results indicated that the inhibitory effect was almost immediate. Although the inhibitory effect of anti-UTI-III serum on UTI-III was almost of the same degree of completeness for the three assay methods. UTI-I was partially inhibited by the anti-UTI-I serum when residual trypsin activity was measured by the caseinolytic or fibrinolytic assay method. This discrepancy was considered to be due to the difference in conformational change between UTI-I and UTI-III by antigen-antibody reaction.
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PMID:Immunochemical studies of human urinary trypsin inhibitor. 616 69

The isolation and characterization of three protease inhibitors from tracheobronchial secretions are described. As starting material, pooled secretions from patients with tracheostomies was used. The isolation procedure consisted of precipitation with 3% perchloric acid (the major acid-stable inhibitors remain in solution), affinity chromatography on trypsin-Sepharose, and preparative zone electrophoresis. We found three distinct inhibitors. One was a basic protein with evidence of size and charge heterogeneity but immunologic homogeneity, Mr = 15,850 +/- 1200 daltons, 12,600 +/- 700, 6500 +/- 500. Two inhibitors were acidic proteins, Mr = 63,400 +/- 3200 (AI) and 19,960 +/- 1500 (AII) daltons. The basic inhibitor had tyrosine as the sole aminoterminal amino acid. For the two acidic inhibitors, an aminoterminus was not found. All three inhibitors contained neutral sugars and amino sugars but no sialic acid. They inhibit trypsin, chymotrypsin, and human granulocytic elastase. The two acidic inhibitors are immunologically related; they are apparently derived from serum ITI. Inhibitor AII originates from inhibitor AI, probably by limited proteolysis by several proteases. The concentration of the basic inhibitor in bronchial secretions of 42 patients with obstructive lung disease was 0.206 +/- 0.15 mg/ml.
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PMID:Protease inhibitors in tracheobronchial secretions. 618 75

The inhibitory properties of HI-14 and BI-14, the active 14-kDa parts released from the corresponding human and bovine inter-alpha-trypsin inhibitors, are compared. The structurally homologous inhibitors composed of two tandem Kunitz-type domains differ in their inhibitory specificity, although the reactive site residue in position P1 is occupied by identical (arginine in the C-terminal domain II) or similar (methionine and leucine in the N-terminal domain I of HI-14 and BI-14, respectively) amino-acid residues. The N-terminal domain I of HI-14 is completely inactive against chymotrypsin and pancreatic elastase, whereas BI-14 is a strong inhibitor of these enzymes. Elastase from polymorphonuclear granulocytes interacts with both inhibitors but with different affinities. Compared with the bovine inhibitor, the human inhibitor shows a much lower affinity from this enzyme. Human ITI and its physiological 30-kDa derivative (HI-30) show the same inhibitory properties as HI-14. The differences between human and bovine inhibitors might be explained by a preceding oxidation of Met in vivo of the reactive site residue in position P1 and/or by the influence of the environmental parts connected with this antielastase reactive site region in human ITI or in the active domains thereof.
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PMID:Elastase inhibition by the inter-alpha-trypsin inhibitor and derived inhibitors of man and cattle. 619 78


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