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)

Limited proteolysis of myosin by such proteolytic enzymes as trypsin, chymotrypsin or papain produces typical fragmentation of its heavy chain. Presently evidence is given that trypsin treatment cleaves the alkali light chain A-1 (20,700 dalton) to a shorter (ca 20,000 dalton) chain. The two "essential" thiols (SH-1 and 2) of moysin were alkylated with 17-C-N-ethylmaleimide and a non-negligible amount of radioactivity was also found in the two alkali light chains. Using the specific radioactivity of alkali light chain A-1 it was possible to identify it among heavy chain fragmentation products. The molecular weight of the newly formed A-1 indicates that limited tryptic cleavage of this A-1 confers on it a closer similarity with alkali light chain A-2.
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PMID:[Fragmentation of myosin A-1 light chain of fast muscle by trypsin]. 11 21

The heavy chain fragmentation pattern of native myosin when digested by proteolytic enzymes is influenced by such conditions as the nature of the proteolytic agent, ionic strength and presence or absence of divalent cations. HMM and S-1 produced by digestion of 14CNEM-labelled myosin under various conditions were analyzed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis. Purified samples of these species were digested under controlled conditions by chymotrypsin and trypsin and a comparison of the observed heavy chain fragmentation patterns led to a sequential arrangement of the proteolytic fragments. The main features of this arrangement are the following: a 21K molecular weight tryptic peptide is found at the N-terminal side of myosin heavy chain. Adjacent to it is a 48K peptide, then a 19.5K peptide containing the two SH-1 and SH-2 thiols. These three peptides constitute the heavy chain of S-1. Adjacent to this S-1 heavy chain is a tryptic (and also chymotryptic) 40K peptide. The rest of the HMM heavy chain on the C-terminus is a sequence susceptible to both chymotrypsin and trypsin attack yielding an undefined number of small peptides.
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PMID:Proteolytic fragmentation of myosin: location of SH-1 and SH-2 thiols. 11 42

1. Prolonged treatment of coupling factor I (CF1) from spinach chloroplasts with trypsin free of chymotrypsin yielded an active ATPase. The isolated preparation showed only two polypeptide chains (mol wt 55,000 to 60,000) on acrylamide gels run in the presence of sodium dodecyl sulfate. The three smaller subunits of CF1 were not detectable. The preparation no longer served as a coupling factor for photophosphorylation in either EDTA- or silicotungstate-treated chloroplasts. 2. An antiserum prepared against coupling factor I from chloroplasts inhibited the ATPase activity of the trypsin-treated CF1. In contrast, antisera prepared against the two individual (denatured) subunits did not inhibit the ATPase activity when tested either alone or together, although each interacted with the trypsin-treated protein, forming precipitin lines in Ouchterlony plates. 3. The trypsin-treated enzyme was still cold-labile, showing that the three smaller subunits are not required for this property. However, the enzyme was no longer sensitive to the natural inhibitor protein which is one of its subunits (subunit epislon), but was still sensitive to inhibition by the flavonoid quercetin. 4. Two equivalents of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole were sufficient to inhibit about 80% of the ATPase activity of the coupling factor, irrespective of whether it contained two of five subunits. The inhibition was completely reversed by dithiothreitol. 5. Triated 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole was prepared. Treatment of the coupling factor with this tritium-labeled inhibitor followed by electrophoresis on acrylamide gels revealed that most of the radioactivity was incorporated into the beta subunit of the enzyme (molecular weight 56,000).
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PMID:Partial resolution of the enzymes catalyzing photophosphorylation. XV. Approaches to the active site of coupling factor I. 12 75

BCG cell walls contain approximately 30% free lipids like other mycobacterial cell walls. The insoluble skeleton of the cell wall is made up of two covalently linked polymers, a peptidoglycan and an arabinogalactan mycolate, with which are associated non peptidoglycan amino acids and a glucan. We present data on two structural features: 1. The "non peptidoglycan" amino acids; they form two kinds of compounds: peptide chains which can be solubilized by proteolytic enzymes and a trypsin-chymotrypsin insensitive poly-alpha-L-glutamic acid. 2. Presence of meso-DAP-meso-DAP1) interpeptide linkages in the peptidoglycan: this new type represents at least 50% of the interpeptide linkages of the cell wall of the BCG strain.
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PMID:Chemical structure of the cell wall of Mycobacterium tuberculosis var. bovis, strain BCG. 12 48

Proteoglycan from pig costal cartilage and fragments obtained by proteolytic digestion were characterized by equilibrium ultracentrifugation and amino acid analysis. The proteoglycan extractable in 4 M guanidinium chloride yielded, after proteolytic digestion with trypsin and chymotrypsin, a chondroitin sulfate peptide containing four chains of polysaccharide. The unextractable residue yielded chondroitin sulfate peptide containing only two chains. The amino acid composition indicated a fairly uniform spacing between all four chains with an average of eight amino acid residues between the serine residues involved in linkage. Following the alkaline sulfite elimination-addition reaction, free peptide was isolated and found to contain one unsubstituted serine residue for every two linked glycosidically. Glycine and glutamic acid were the only two amino acids sufficiently abundant to be part of an invariant sequence near to serine residues destined to be glycosylated. The linkage region of the polypeptide also contains some substituted serine residues which do not carry a full chondroitin sulfate chain.
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PMID:The linkage region in the polypeptide of pig costal cartilage proteoglycan. 12 39

In this paper we describe new and so far unknown protease inhibitors present in the tentacles of the annelid Sabellastarte indica Savingny. At least five different isoinhibitors with inhibitory activity towards trypsin, plasmin, chymotrypsin and kallikrein can be separated electrophoretically. Our protease inhibitor active material differs from the other well known protease inhibitors found in invertebrates in its high molecular weight, in that it is heat-labile and in the occurrence of the isoelectric point in the weakly acid region. On the other hand, the new protease inhibitors have some similarities to the soybean inhibitor described by Kunitz, and to ovomucoid. We also discuss the possibility that these inhibitors may influence the fibrinolytic system.
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PMID:[New protease-inhibitors with broad specificity in the polychaet Sabellastarte indica (Savingny), I (author's transl)]. 12 15

The reactive-site sequence of a proteinase inhibitor can be written as . . . -P3-P2-P1-P'1-P'2-P'3- . . . , where-P1-P'1-denotes the reactive site. Three semisynthetic homologues have been synthesized of the bovine trypsin-kallikrein inhibitor (Kunitz) with either arginine, phenylalanine or tryptophan in place of the reactive-site residue P1, lysine-15. These homologues correspond to gene products after mutation of the lysine 15 DNA codon to an arginine, phenylalanine or tryptophan DNA codon. Starting from native (virgin) inhibitor, reactive-site hydrolyzed, still active (modified) inhibitor was prepared by chemical and enzymic reactions. Modified inhibitor was then converted into inactive des-Lys15-inhibitor by reaction with carboxypeptidase B. Inactive des-Lys15-inhibitor was reactivated by enzymic replacement of the P1 residue according to Leary and Laskowski, Jr. The introduction of arginine was catalyzed by an inverse reaction with carboxypeptidase B, while phenylalanine or tryptophan were replaced by carboxypeptidase A. The reactivated semisynthetic inhibitors were trapped by complex formation with either trypsin or chymotrypsin. The enzyme - inhibitor complexes were subjected to kinetic-control dissociation, and the semisynthetic virgin inhibitors were isolated. The inhibitory properties of the semisynthetic inhibitors have been investigated against bovine trypsin and chymotrypsin and against porcine pancreatic kallikrein and plasmin. The homologues with either lysine or arginine in the P1 position are equally good inhibitors of trypsin, plasmin and kallikrein. The Arg-15-homologue is a slightly more effective kallikrein inhibitor than the Lys15-inhibitor. The semisynthetic phenylalanine and tryptophan homologues, however, are weak inhibitors of trypsin and still weaker inhibitors of kallikrein, but are excellent inhibitors of chymotrypsin. Their association constant with chymotrypsin is at least ten times higher than that of native Lys-15-inhibitor. A dramatic specificity change is observed with the phenylalanine and tryptophan homologues, which in contrast to the native inhibitor do not at all inhibit porcine plasmin. Thus, the nature of the P1 residue strongly influences the primary inhibitory specificity of the bovine inhibitor (Kunitz).
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PMID:Replacement of lysine by arginine, phenylalanine and tryptophan in the reactive site of the bovine trypsin-kallikrein inhibitor (Kunitz) and change of the inhibitory properties. 12 27

Trypsin (T) and chymotrypsin (CHT) activities in luminal contents of the ileum, caecum and sigmoideum were followed in conventional (6 animals), monoassociated (5) and germfree (5) rabbits by pH-stat automatic titration using p-toluenesulphonyl-L-arginine methylester and acetyl-L-tyrosine ethylester as substrates. In conventional rabbits with complete microbial flora an aborally increasing decline of both proteolytic activities of luminal contents was determined (ileum T 198.2 - CHT 100.0; signmoideum T 10m.2 - CHT 68.8 mrg/g of intestinal content). Monoassociated animals represent a group different from both germfree and conventional animals. Trypsin and chymotrypsin of intestinal contents were not significantly altered by the presence of megacaecum in germfree rabbits (ileum T 219.2 - CHT 160.2; sigmoideum T 208.8 - CHT 110.8 mug/g of intestinal content). Chymotrypsin in the intestinal contents appears more labile and more affected by microbial flora than trypsin.
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PMID:Trypsin and chymotrypsin activity of the intestinal content in germfree, monoassociated and conventional rabbits. 13 38

Purified (Na+, K+)-activated adenosine triphosphatase ((Na+, K+)-ATPase, ATP phosphohydrolase, EC 3.6.1.3) has been subjected to trypsin and chymotrypsin hydrolysis. The glycoprotein is much more resistant to proteolysis than the large chain. This differential susceptibility to proteolysis is not due to differences in the number of trypsin or chymotrypsin sensitive bonds because the two subunits are equally susceptible to proteolysis after isolation by preparative gel electrophoresis in sodium dodecyl sulfate. It is also not due to steric "shielding" of the glycoprotein by the large chain or its proteolytic products: (1) The rate of digestion of the glycoprotein is not increased after 90% of the large chain is digested. (2) The majority of the large chain peptides are released into the supernatant upon degradation. It is concluded that the greater resistance of the glycoprotein to proteolysis is due to its native conformation. In the absence of the large chain, the susceptibility of the glycoprotein to tryptic degradation by K+ and Na+. The evidence suggests that this decreased susceptibility was due to conformational changes in the glycoprotein. These specific ligand effects on proteolysis of the glycoprotein suggests that the glycoprotein may participate in Na+ and K+ binding by (Na+, K+)-ATPase.
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PMID:The susceptibility of the glycoprotein from the purified (Na+, K+)-activated adenosine triphosphatase to tryptic and chymotryptic degradation with and without Na+ and K+. 13 66

Four natural protease inhibitors have been partially purified by heat treatment, ion-exchange chromatography pand gel filtration from Neurospora crassa. The inhibitory activity has been estimated by measuring the inhibition of proteolysis of casein as well as by the protection of Neurospora tryptophan synthase from proteolytic inactivation. The inhibitors are all oligopeptides and possess molecular weights in the range 5000-24 000 and appear to be very specific to Neurospora proteases. They may be classified into two types. The first are specific to Neurospora alkaline protease and the second to acidic protease. None of them exhibited any effect on other proteases including trypsin, chymotrypsin, papain, pepsin, thermolysin, subtilisin and proteinase K. The possible physiological role of these inhibitors is discussed.
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PMID:Isolation of specific protease inhibitors from Neurospora crassa. 13 53


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