Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The C-peptide immunoreactivity (CPR) is markedly increased after a short incubation of human plasma with trypsin. Three experiments (study of the action of trypsin-treated plasma on labelled CPR, precipitation of plasma proteins with polyethylene glycol, CPR measurement with three different radioimmunoassays kits) were made in order to account for this phenomenon. The concordant results obtained and the inhibitory action of aprotinin observed in these experiments led us to conclude to the existence in plasma of a trypsin dependent C-peptidase with a specificity for the COOH terminus of the complete CPR (Arg - Arg - C-peptide - Lys - Arg). The role of this protease is probably minor in the C-peptide degradation process but could have an effect on the insulin catabolism through the existence of the alpha 2 - macroglobulin - trypsin complexes and insulin protease. This suggests a possible influence of the exocrine pancreas on the endocrine pancreas.
 ...
PMID:In vitro existence of a trypsin dependent C-peptidase in human plasma. Discussion of its possible role in vivo. 634 Jun 76

The proteolytic enzymes contained in the preparation from Streptomyces 771 have been separated by isoelectric focusing in the sucrose density gradient at pH 3-10. The following enzymes have been identified: three multiple forms of neutral metal proteinase (pI 5.1, 6.37, 7.8) each of which splits DNP-Gly-Gly decreases-Val-ArgOMe; elastase-like metal proteinase active with respect to RBB-elestin with pI 10.68; metal-dependent peptidases: leucin aminopeptidase active with respect to L-RBB-elastin with pI 10.68 metal-dependent peptidases: leucin aminopeptidase active with respect to L-leucin n-nitroanilide and L-leucin beta-naphtylamide with pI 7.65, 7.15, 6.67, 6.45, 5.7, 5.35, 5.22, 4.83; carboxy peptidase with pI 5.95, 6.37; serine metal-dependent subtilisin-like proteinase active with respect to 2-Ala-Ala-LeupNA, 2-Gly-Gly-LeupNA, 2-Ala-LeupNA; two multiple forms of serine trypsin-like proteinase active with respect to BAEE and BApNA with pI 4.35, 4.76; serine chymotrypsin-like proteinase with pI 8.68 active with respect to ATEE.
 ...
PMID:[Isoelectric focusing of a preparation of proteolytic enzymes from Streptomyces 771]. 634 61

The purification of detergent-solubilized kidney microvillar endopeptidase (EC 3.4.24.11) by immuno-adsorbent chromatography is described. The product (the d-form) was 270-fold purified compared with the homogenate of kidney cortex and was obtained in a yield of 5%. It was free of other peptidase activities and homogeneous by electrophoretic analyses. It contained about 15% carbohydrate and one Zn atom/subunit. Two trypsin-treated forms were also characterized. One (dt-form) was obtained by treatment of the d-form. The other (tt-form) was the result of solubilizing the membrane by treatment with toluene and trypsin. All three forms had apparent subunit Mr values of approx. 89 000, but the d-form appeared to be slightly larger than the other two. Estimates of Mr by gel filtration showed that of the tt-form to be 216 000 whereas those of the other forms were 320 000. An estimate of the detergent (Triton X-100) bound to the d- and dt-forms accounted for this difference. By several criteria, including charge-shift crossed immunoelectrophoresis and hydrophobic chromatography, the d- and dt-forms were shown to be amphipathic molecules. In contrast, the tt-form was hydrophilic in its properties. Differences in ionic properties were also noted, consistent with the loss, in the case of the dt-form, of a positively charged peptide. The results indicate that the native endopeptidase is a dimeric molecule, each subunit being anchored in the membrane by a relatively small region of the polypeptide close to one or other terminus. The d- and dt-forms had similar enzyme activity when assayed by the hydrolysis of 125I-insulin B-chain. Chelating agents and phosphoramidon inhibited the endopeptidase. The kinetic constants were determined by a new two-stage fluorimetric assay using glutarylglycylglycylphenylalanine 2-naphthylamide as substrate and aminopeptidase N (EC 3.4.11.2) to hydrolyse phenylalanine 2-naphthylamide. The Km was 68 microM and Vmax. 484nmol X min-1 X (mg of protein)-1.
 ...
PMID:Proteins of the kidney microvillar membrane. The amphipathic forms of endopeptidase purified from pig kidneys. 634 15

Leader peptidase typifies a group of proteins of the plasma membrane of E. coli which span the membrane and are synthesized without a cleaved amino-terminal leader (signal) sequence. The membrane assembly properties of these proteins have not been previously reported. We find that the membrane electrochemical potential is necessary for the insertion of a large domain of leader peptidase across the membrane. In the absence of potential, the peptidase accumulates inside the cell in tight association with the plasma membrane. Upon restoration of the potential, accumulated peptidase inserts across the membrane, indicating that this insertion is not mechanistically coupled to polypeptide chain growth. The normal, trans-bilayer peptidase and that which accumulates in the absence of potential have different conformations, as shown by the relative resistance of the trans-bilayer enzyme to digestion by trypsin or chymotrypsin in cell lysates. Membrane insertion is accompanied by this conformational change. This assembly reaction has several features predicted by the hypothesis of membrane-triggered folding.
 ...
PMID:Bacterial leader peptidase, a membrane protein without a leader peptide, uses the same export pathway as pre-secretory proteins. 636 3

Two peptidases which convert 125I-Lys-Arg-ME and 125I-ME-Arg6, respectively, to 125I-ME, have been identified and characterized in bovine adrenomedullary chromaffin granules. The former is referred to as a secretory granule peptidase (SGP) and the latter as a carboxypeptidase B-like enzyme (CPB-like) [7] which is here further characterized. SGP cleaved 125I-Lys-Arg-ME to produce only 125I-ME and was localized in chromaffin granules which contained Co2+-stimulated CPB-like activity, ME, and catecholamines. Both the SGP and the CPB-like enzymes appear to be thiol-metalloproteases. While the CPB-like enzyme seems likely to be involved in processing the enkephalin precursors [7], SGP may function as a trypsin-like or aminopeptidase enzyme in secretory granules.
 ...
PMID:Two peptidases that convert 125I-Lys-Arg-(Met)enkephalin and 125I-(Met)enkephalin-Arg6, respectively, to 125I-(Met)enkephalin in bovine adrenal medullary chromaffin granules. 637 57

The complete amino acid sequence of the larger (alpha-) subunit and about 70% of the total sequence of the smaller (beta-) subunit of the MoFe protein from Clostridium pasteurianum was determined by analyses of peptides derived from BrCN cleavage and by digestions with trypsin, staphylococcal protease and lysylendo-peptidase of the separated subunits. The alpha-subunit has 529 amino acid residues, giving an Mr value of 58 774. This is the first complete sequence for the alpha-subunit of an isolated MoFe protein. In comparing the sequences of both subunits to those from other sources, 5 out of 9 cysteines in the alpha-subunit and 3 out of 6 in the beta-subunit are invariant, thus suggesting a function as ligands to FeS and MoFeS clusters in the MoFe protein. All of these cysteines are located in the amino terminal halves of both subunits.
 ...
PMID:Structural homologies between the amino acid sequence of Clostridium pasteurianum MoFe protein and the DNA sequences of nifD and K genes of phylogenetically diverse bacteria. 658 89

1. Enzymic hydrolysis of amino acid derivatives of benzocaine occurs with homogenates of rat muscle, kidney, liver and other tissues, and in human blood serum. 2. Marked differences in rates of hydrolysis depend on the type of tissue and the nature of the amino acid moiety. The highest rate of hydrolysis was observed with kidney and with DL-leucylbenzocaine as substrate; N,N-dimethylglycylbenzocaine was the poorest substrate. 3. Enzymic hydrolysis of amino acid derivatives of benzocaine was catalysed by leucylaminopeptidase, 'pronase', 'peptidase' and by proteolytic enzymes in duodenal juice. Purified preparations of pepsin, trypsin and chymotrypsin do not catalyse hydrolysis.
 ...
PMID:Enzymic hydrolysis of amino acid derivatives of benzocaine. 675 55

The neurointermediary lobes from 190 rat pituitaries were homogenized in an acidic medium which inhibits peptidase activity and maximizes the solubilization of undamaged peptides. Octadecylsilyl-silica (ODS-silica) was used to extract the supernatant of the tissue homogenate. The ODS-silica eluate, now largely protein and salt free, was subjected to reversed-phase high-performance liquid chromatography (HPLC) employing 0.1% trifluoroacetic as counter ion. The column eluates were monitored for beta-endorphin immunoreactivity. Five immunoreactive components were observed. The most hydrophobic of these was repurified on the same HPLC column using 0.13% heptafluorobutyric acid as counter ion. Characterization of the purified peptide by gel permeation HPLC, amino acid analysis, and tryptic fragmentation indicated that it corresponded in structure to alpha-N-acetyl-beta-endorphin1-26. Amino acid analysis of the native peptide and its trypsin and carboxypeptidase fragments indicated that an alanyl residue occupies position 26. This finding is in contrast to the sequence predicted for the beta-lipotropin/corticotropin precursor by recombinant DNA techniques which suggests that the 26th residue of the beta-endorphin molecule should be valine.
 ...
PMID:alpha-N-acetyl-beta-endorphin1-26 from the neurointermediary lobe of the rat pituitary: isolation, purification, and characterization by high-performance liquid chromatography. 684 89

Mutants of Candida utilis and a haploid strain of Saccharomyces cerevisiae were isolated, after ultraviolet light mutagenesis, which had increased sensitivities to snail gut enzymes (ses). Three of the five S. cerevisiae mutants tested had increased sensitivities to porcine pepsin, all were more susceptible to a sequential treatment with pepsin, lipase, peptidase, and trypsin, four were sensitive to osmotic shock, and two had increased glucan/mannan ratios in their cell walls. All combinations of mutants showed positive complementation in heterozygous diploids, although complementation between one pair, which had the same phenotype, was incomplete, indicating that four to five different cistrons were involved. All mutations were found to be recessive. Haploid strains bearing pairs of ses mutations were not markedly more sensitive to mammalian digestive enzymes than strains with single mutations. Rat-feeding experiments with three mutants and the parental strains indicated that the protein was efficiently utilized in all cases. Net protein ratios for the two mutants of S. cerevisiae tested were slightly higher than that for their parent, but the differences were of marginal significance.
 ...
PMID:Mutants of Saccharomyces cerevisiae and Candida utilis with increased susceptibility to digestive enzymes. 701 34

The influence of proteinases on monkey cervical glycoproteins was investigated to assess their effect on cervical mucus and, thereby, on sperm penetration. The major component of periovulatory cervical mucus, a high molecular weight glycoprotein, was treated with Pronase, trypsin, chymotrypsin, papain, and bovine seminal peptidase, and the enzyme-resistant glycoprotein was purified by gel filtration on Sepharose 2B. A macromolecular component in high yield was recovered containing carbohydrate and protein moieties. Asialoglycoprotein, on treatment with Pronase, trypsin, and bovine seminal peptidase released more than one glycoprotein fragment. The carbohydrate and amino acid components of the native and degraded glycoproteins were similar in composition with variations in proportions. The structure of the carbohydrate-rich, pronase-resistant glycoprotein, further purified on Sepharose 2B, was examined. Sequential Smith degradation and methylation of the degraded glycoprotein fragment established a structure that shows some differences to that of the native glycoprotein. The influence of proteinases on cervical-mucus glycoproteins and a possible mechanism of sperm penetration through Pronase-treated glycoproteins is discussed.
 ...
PMID:Studies on bonnet monkey cervical mucus. The effect of proteases on mucus glycoproteins of Macaca radiata. 703 4


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>