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 DNA polymerase was isolated from human spermatozoa. In one procedure, spermatozoa were decapitated with detergent, the heads purified and then lysed with dithiothreitol, trypsin and deoxyribonuclease. DNA polymerase was isolated from the lysate by sedimentation through an 18% Metrizamide solution, solubilization with 0.8 M-KCl-0.5% Triton X-100 and sequential chromatography on DEAE cellulose, phosphocellulose and hydroxylapatite. Alternatively, the heads of intact spermatozoa, untreated with detergent, were lysed as above; the subsequent Metrizamide pellet fraction was isolated and further fractionated by gel filtration and buoyant density centrifugation. The enzyme in this fraction was solubilized with KCl-Triton X-100. Characterization by velocity centrifugation and phosphocellulose chromatography revealed that it possessed properties indistinguishable from those of the enzyme purified from isolated sperm nuclei. The DNA polymerase had an apparent molecular weight of 79,000-89,000, Mn2+ (1 mM) was the preferred divalent cation and ativity was inhibited by concentrations of potassium phosphate greater than 10 mM. The synthetic template preferences of the enzyme were dT12-18 . poly rA > poly(dA-dT) > dT12-18 . poly dA; no activity was observed with dG12-18 . poly rC or dT10.
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PMID:Properties of a DNA polymerase from purified nuclei and DNA-synthesizing complexes of human spermatozoa. 743 Dec 98

The percentage of bacteriocin-producing and phage-producing Klebsiella strains was as follows: K. pneumoniae-10%, K. ozaenae-7%, K. rhinoscleromatis-9%. The antimicrobial spectrum of the studied inducible particler was broad and was not limited by the frames of the genus and family. Bacteriocins and bacteriophages from Klebsiella were active to Klebsiella, Enterobacter, Escherichia, Shigella and Proteus representatives significant in medicine. Klebocins and Klebsiella phages exhibited antagonistic effects to phytopathogenic bacteria. Some strains of Erwinia and Pseudomonas were sensitive to phages or bacteriocins from Klebsiella. Bacteriocins protected corn and tomato seeds from contamination by erwinioses agents. All cultures of Agrobacterium, Corynebacterium, Micrococcus, Staphylococcus, Streptococcus were resistant to action of phages and klebocins. Bacteriocins from Klebsiella were assayed for their sensitivity to trypsin, chymotrypsin, lysozyme, ribonuclease, deoxyribonuclease. Action of klebocins was associated with a protein component. Proceeding from data of diffusion through the disc ultrafiltration membranes molecular weight of klebocins was in the range of 30,000 and 50,000 Da.
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PMID:[The antimicrobial spectrum of the action of bacteriocins and bacteriophages from Klebsiella strains]. 816 98

We recently described the pre-steady state enzymatic binding kinetics of apurinic/apyrimidinic endonuclease (AP endo). In this report we describe the domain structure of the enzyme in solution determined by mild protease digestion in the presence and absence of substrate, product, and an efficient competitive inhibitor (HDP). AP endo is a 35.5-kDa protein with a high degree of homology to its prokaryotic counterpart, exonuclease III (Exo III), except for the amino terminus, which is lacking in the prokaryotic enzyme. The entire conserved region plus an additional 20 residues unique to the eukaryotic enzyme was inaccessible to trypsin and V8 protease, indicating that it forms a tight globular structure. In contrast, the amino-terminal 35 residues were readily accessible to all the proteases investigated, leading us to conclude that they associate poorly with the rest of the structure and constitute a highly fluid region. When AP endo was boiled with SDS and cooled prior to the addition of V8 protease, several acidic residues within the globular domain became protease-accessible, indicating rapid renaturation except along the nuclease fold with restoration of globular conformation for the carboxyl two-thirds of the molecule. Of all the proteases tested, only chymotrypsin was able to cleave internal to the globular portion without prior denaturation. Although AP endo cleaved with chymotrypsin retained full enzymatic activity, the activity was lost when the digested peptides were recovered after denaturation by heat and/or boiling in SDS, precipitation, and renaturation or when fragments were recovered from an SDS gel and renatured. Thus, the protein is probably held together strongly by noncovalent interactions that maintain enzymatic function after protease nicking. The three major chymotrypsin cleavage sites, Tyr-144, Leu-179, and Leu-205, became strikingly less accessible to protease digestion in the presence of abasic site-containing DNA. Since the three residues form a spherical triangle on the surface of the molecule on one side of the nuclease fold, there must be multiple means by which DNA containing an abasic site associates with the enzyme. The most likely explanation is that substrate and product, both of which were present during proteolysis, bind differently to the enzyme. Finally, the two cysteine residues thought to be involved in the redox reaction of AP endo with Jun protein were entirely inaccessible to proteolysis even after prolonged exposure of AP endo to reducing agents. Consequently, if AP endo plays a role in the physiological function of Jun, it must undergo major conformational changes in the process. Alternatively, the two cysteines could maintain an appropriate conformation such that other residues participate directly in the redox activity.
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PMID:Domain mapping of human apurinic/apyrimidinic endonuclease. Structural and functional evidence for a disordered amino terminus and a tight globular carboxyl domain. 960 56

Transglutaminases catalyze the cross-linking and amine incorporation of proteins, and are implicated in various biological phenomena such as blood clotting, wound healing, apoptosis, and cell differentiation. Streptomyces lavendulae Y-200, isolated from soil, produced a substance that inhibited transglutaminases. The inhibitory substance was purified from the cultured medium by procedures of acid precipitation, deoxyribonuclease treatment, and gel filtration chromatography. The partially purified sample was dark brown. The inhibitory activity was stable under acidic, alkaline, and high temperature conditions, and resistant to the treatment with proteinases such as trypsin and Pronase. The molecular weight of the inhibitory substance was estimated to be between 10(4) and 10(5) from its permeability through ultrafilter membranes. The acid hydrolysate of the inhibitory substance contained amino acids and sugars. The inhibitory substance inhibited both calcium-dependent and calcium-independent transglutaminases in a competitive manner with a glutamine substrate. The extent of inhibition caused by the calcium-dependent transglutaminase increased with increasing calcium concentration. The results obtained here may help identify a novel regulatory substance of transglutaminase in biological systems.
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PMID:High molecular weight transglutaminase inhibitor produced by a microorganism (Streptomyces lavendulae Y-200). 1070 56

We asked whether the antiangiogenic action of 16K human PRL (hPRL), in addition to blocking mitogen-induced vascular endothelial cell proliferation, involved activation of programmed cell death. Treatment with recombinant 16K hPRL increased DNA fragmentation in cultured bovine brain capillary endothelial (BBE) and human umbilical vein endothelial (HUVE) cells in a time- and dose-dependent fashion, independent of the serum concentration. The activation of apoptosis by 16K hPRL was specific for endothelial cells, and the activity of the peptide could be inhibited by heat denaturation, trypsin digestion, and immunoneutralization, but not by treatment with the endotoxin blocker, polymyxin-B. 16K hPRL-induced apoptosis was correlated with the rapid activation of caspases 1 and 3 and was blocked by pharmacological inhibition of caspase activity. Caspase activation was followed by inactivation of two caspase substrates, poly(ADP-ribose) polymerase (PARP) and the inhibitor of caspase-activated deoxyribonuclease (DNase) (ICAD). Furthermore, 16K hPRL increased the conversion of Bcl-X to its proapoptotic form, suggesting that the Bcl-2 protein family may also be involved in 16K hPRL-induced apoptosis. These findings support the hypothesis that the antiangiogenic action of 16K hPRL includes the activation of programmed cell death of vascular endothelial cells.
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PMID:The antiangiogenic factor 16K PRL induces programmed cell death in endothelial cells by caspase activation. 1104 70

We previously demonstrated the stimulation of human apurinic/apyrimidinic endonuclease 1 (HAP1) by heat shock protein 70 (HSP70). In this work, we further defined the functional interaction between these proteins. Digestion of HSP70 by trypsin released 48 and 43 kDa amino terminal fragments that retained the ability to stimulate HAP1. In agreement with this result, an HSP70 N-terminal deletion mutant protein containing amino acids 1-385 was comparable to the full-length protein in its ability to enhance HAP1 activity. HSP70 mutants containing carboxy terminal amino acids 386-640 stimulated HAP1 only slightly, as did unrelated proteins. These results implicate the amino terminal portion of HSP70 in stimulating the activity of HAP1.
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PMID:Specific stimulation of human apurinic/apyrimidinic endonuclease by heat shock protein 70. 1254 89

Hydrogen bonded histidine-aspartate (His-Asp) pairs are critical constituents in several key enzymatic reactions. To date, the role that these pairs play in catalysis is best understood in serine and trypsin-like proteases, where structural and biochemical NMR studies have revealed important pK(a) values and hydrogen bonding patterns within the catalytic pocket. However, the role of the His-Asp pair in metal-assisted catalysis is less clear. Here, we apply liquid-state NMR to investigate the role of a critical histidine residue of apurinic endonuclease 1 (Ape1), a human DNA repair enzyme that cleaves adjacent to abasic sites in DNA using one or more divalent cations and an active-site His-Asp pair. The results of these studies suggest that the Ape1 His-Asp pair does not function as either a general base catalyst or a metal ligand. Rather, the pair likely stabilizes the pentavalent transition state necessary for phospho-transfer.
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PMID:Investigation of the role of the histidine-aspartate pair in the human exonuclease III-like abasic endonuclease, Ape1. 1275 78

Banerjea, A. (Rocky Mountain Laboratory, Hamilton, Mont.) and J. Munoz. Antigens of Bordetella pertussis. II, Purification of heat-labile toxin. J. Bacteriol. 84:269-274. 1962.-A mild method of separating heat-labile toxin of Bordetella pertussis from other cellular components is described; it consists of absorbing toxin on a diethylaminoethyl cellulose column and eluting it with a gradient concentration of NaCl. Toxin preparations thus obtained consisted mainly of protein; their toxicity was destroyed by trypsin but not by ribonuclease or deoxyribonuclease.
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PMID:Antigens of Bordetella pertussis. II. Purification of heat-labile toxin. 1386 10

A method for the isolation of metaphase chromosomes from mouse L1210 leukemia cells has been developed. Cells, arrested at metaphase with colchicine, were exposed to hypotonic solution and the pH was then adjusted to 5.6 to stabilize the chromosomes. The metaphase figures were subsequently disrupted and the chromosomes isolated by a series of differential centrifugations in sucrose. The isolated chromosomes were well preserved, as judged by morphological criteria. The effect of various enzymes and chemical agents on the isolated chromosomes was studied. Chymotrypsin, trypsin, and deoxyribonuclease caused a marked disintegration of the chromosomes, whereas treatment with pepsin and ribonuclease induced no significant morphological alterations.
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PMID:STUDIES ON THE ISOLATION OF METAPHASE CHROMOSOMES. 1406 2

The various cellular components of immune rabbit histiocytes have been analyzed for their ability to induce cellular resistance in normal animals. The results of these investigations have shown that the nuclear and mitochondrial fractions were inactive and that the microsomal and ribosomal fractions were active. The importance of ribonucleic acid in induction of cellular resistance was established by isolation of an active ribosomal RNA and by demonstration of inactivation of this material with ribonuclease but not with deoxyribonuclease or trypsin. The possibility that viable bacilli were present in immune ribosomes was tested; the absence of complement-fixing antibodies and of skin reactivity to tuberculin in animals inoculated with ribosomes was considered as partial evidence of absence of living bacilli.
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PMID:STUDIES OF TUBERCLE BACILLUS-HISTIOCYTE RELATIONSHIPS. VI. INDUCTION OF CELLULAR RESISTANCE BY RIBOSOMES AND RIBOSOMAL RNA. 1407 98


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