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)

Leader peptidase is an enzyme of the Escherichia coli cytoplasmic membrane which removes amino-terminal leader sequences from many secreted and membrane proteins. Three potential membrane-spanning segments exist in the first 98 amino acids of leader peptidase. We have characterized the topology of leader peptidase based on its sensitivity to protease digestion. Proteinase K and trypsin treatment of right-side-out inner membrane vesicles and spheroplasts yields protected fragments of approximately 80 and 105 amino acid residues, respectively. We have shown that both fragments are derived from the amino terminus of the protein and that the smaller protected peptide can be derived from the larger. Removal of the third potential membrane-spanning segment (residues 82-98) does not affect the size of the proteinase K-protected fragment but does reduce the size of the trypsin-protected peptide. Because the proteinase K-protected fragment is about 9000 daltons, is derived from the amino terminus of leader peptidase, and its size is not affected when amino acids 82-98 are removed from the protein, it must extend from the amino terminus to approximately residue 80. Likewise, the trypsin-protected fragment must extend from the amino terminus to about residue 105. These data suggest a model for the orientation of leader peptidase in which the second hydrophobic stretch (residues 62-76) spans the cytoplasmic membrane and the third hydrophobic stretch resides in the periplasmic space.
 ...
PMID:A small hydrophobic domain anchors leader peptidase to the cytoplasmic membrane of Escherichia coli. 303 31

Subtilisin inhibitors (SI) having an average molecular mass of 8 kDa purified from jack beans (Canavalia ensiformis) and broad beans (Vicia faba) to electrophoretical homogeneity are compared to those isolated from chick peas (Cicer arietinum) and black beans (Phaseolus vulgaris). The specificity spectrum of SI is restricted to microbial serine proteinases. Their interaction with subtilisin Carlsberg is variable, obtaining the highest value for black bean, followed by broad bean, chick pea and jack bean inhibitors. Proteinase K reacts with most SI twice as strongly as subtilisin. The reaction of SI with subtilisin apparently follows the "standard mechanism" proposed by Laskowski for the interaction of trypsin with its inhibitors. Accordingly, the reactive site of jack bean, broad bean and black bean SI is reversibly cleaved by subtilisin in acid and neutral solutions, whereas chick pea SI is hydrolysed only at neutral pH values. Judged by similarities in specificity, molecular mass, heat stability and reactive site cleavage, the SI from legume seeds could constitute a new "family" of proteinase inhibitors.
 ...
PMID:Subtilisin inhibitors in legume seeds. 306 Jan 46

Proteinase II, a high-molecular-mass proteinase previously identified in white croaker skeletal muscle, was purified to apparent homogeneity by DEAE-Sephacel, phenyl-Sepharose CL 4B, and Sephacryl S-300 chromatographies. Under denaturing conditions, the enzyme dissociated into a cluster of subunits with Mr ranging from 18,000 to 26,000 and a large subunit with a Mr 60,000. The proteinase was able to hydrolyze N-terminal-blocked 4-methyl-7-coumarylamide substrates having either an aromatic amino acid (chymotrypsin-like activity) or an arginine residue (trypsin-like activity) adjacent to the fluorogenic group. The trypsin-like activity of the enzyme was inhibited by fatty acids and sodium dodecyl sulfate, whereas the chymotrypsin-like activity was stimulated by those compounds but inhibited by nonionic and cationic detergents. Several thiol reagents inhibited both proteinase II activities. However, leupeptin and Cu2+ strongly inhibited its trypsin-like activity but only slightly affected its chymotrypsin-like activity. Dithiothreitol stimulated both activities, but at different extents and in different concentration ranges. These results suggest that the enzyme is multicatalytic, having at least two different active sites.
 ...
PMID:Multicatalytic proteinase in fish muscle. 321 72

Purified B875 light-harvesting complex, chromatophores, and spheroplast-derived vesicles from wild-type Rhodobacter sphaeroides were treated with proteinase K or trypsin, and the alpha and beta polypeptides were analyzed by electrophoretic, immunochemical, and protein-sequencing methods. With the purified complex, proteinase K digested both polypeptides and completely eliminated the A875 peak. Trypsin digested the alpha polypeptide and reduced the A875 by 50%. Proteinase K cleaved the beta polypeptide of chromatophores and the alpha polypeptide of spheroplast-derived vesicles. Sequence analyses of polypeptides extracted from proteinase K-treated chromatophores revealed that the beta polypeptide was cleaved between amino acids 4 and 5 from the N terminus. The N terminus of the alpha polypeptide was intact. We concluded that the N terminus of the beta polypeptide is exposed on the cytoplasmic membrane surface, and the difference in the digestion patterns between the spheroplast-derived vesicles and chromatophores suggested that the C terminus of the alpha polypeptide is exposed on the periplasmic surface.
 ...
PMID:Transverse membrane topography of the B875 light-harvesting polypeptides of wild-type Rhodobacter sphaeroides. 330 52

Proteinase K and trypsin were used to determine the orientation of the light-harvesting B800-850 alpha and beta polypeptides within the chromatophores (inside-out membrane vesicles) of the mutant strain Y5 of Rhodopseudomonas capsulata. With proteinase K 7 amino acid residues of the B800-850 alpha polypeptide were cleaved off up to position Trp-7--Thr-8 of the N terminus, and 11 residues were cleaved off up to position Leu-11-Ser-12 of the beta chain N terminus. The C termini of the B800-850 alpha and beta polypeptides, including the hydrophobic transmembrane portions, remained intact. It is proposed that the N termini of the alpha and beta subunits, each containing one transmembrane alpha-helical span, are exposed on the cytoplasmic membrane surface and the C termini are exposed to or directed toward the periplasm.
 ...
PMID:Localization of the exposed N-terminal region of the B800-850 alpha and beta light-harvesting polypeptides on the cytoplasmic surface of Rhodopseudomonas capsulata chromatophores. 352 57

Recent interest in elucidating the role of non-lysosomal proteases in intracellular protein catabolism in muscle has led to various investigations with three alkaline proteases: a trypsin-like, a chymotrypsin-like, and a high molecular weight cysteine proteinase. Although in vitro biochemical assays have revealed the catabolic potential of at least two of these proteases, confirmation of their presence in muscle cells has been difficult. In this study immunohistochemical techniques were employed to localize each of these proteases in rat myoblasts. Antisera against the trypsin-like and chymotrypsin-like proteinase (both serine proteinases) showed strong localization in the cytoplasm immediately around the nucleus. Both also stained chromatin material in the nucleus of these cells. Fluorescent localization of the high molecular weight cysteine proteinase (Proteinase I) also appeared to be cell-associated in the myoblasts. The use of myoblasts in cell culture sections of whole muscle was advantageous, since localization of the proteases could be assessed in the absence of other cell types.
 ...
PMID:Alkaline proteinase localization in myoblasts. 354 Jan 1

Proteinase inhibitors of microbial origin were injected into the uterine horns of mated rats at 14:00 h on Day 5 of pregnancy (spermatozoa in vaginal smear = Day 1), and 5 or 6 h later the embryos were flushed from the horns and examined. Chymostatin and alpha-MAPI, inhibitors of chymotrypsin-like serine proteinase and thiol proteinases, as well as thiolstatin, an inhibitor of thiol proteinases, significantly inhibited embryo growth. The inhibitory activity of alpha-MAPI on embryonic growth was distinctly greater than that of thiolstatin, although the ID50 values of the two inhibitors to papain are similar. Antipain and leupeptin which are inhibitors of trypsin-like and thiol proteinases, and talopeptin, an inhibitor of metal proteinases, significantly interrupted the removal of the zona pellucida from expanding blastocysts. These results suggest that (1) a chymotrypsin-like proteinase seems to be important to the growth of the embryo, (2) a thiol proteinase may participate in embryonic growth, and (3) a trypsin-like proteinase and a metal proteinase are likely to participate in zonalysis.
 ...
PMID:Effects of proteinase inhibitors on preimplantation embryos in the rat. 383 71

alpha 1-Proteinase inhibitor was purified from porcine blood by ammonium sulphate and Cibachron Blue-Sepharose fractionation, ion exchange chromatography on DEAE-Cellulose, gel filtration on Sephadex G-25, and zinc chelating chromatography. Thus, an inhibitor preparation with a specific activity of 1.62 IU/mg protein (enzyme: trypsin; substrate: BzArgNan) was obtained. In sodium dodecyl sulphate gel electrophoresis one protein band corresponding to a molecular mass of 67.6 kDa was found. On isoelectric focusing 6 protein bands with isoelectric points of 3.80, 3.90, 4.05, 4.20, 4.25 and 4.45 were separated. The amino acid composition was determined. The association rate constants for the inhibition of various serine proteinases were measured.
 ...
PMID:Isolation and characterization of porcine alpha 1-proteinase inhibitor. Leukocyte elastase-inhibitor complexes in porcine blood, I. 387 80

Proteolytic enzymes in extracts of human sperm have been identified and partially characterized using a technique which incorporates gelatin into a sodium dodecyl sulfate-polyacrylamide gel electrophoresis (gelatin-SDS-PAGE) system. Initially, semen characteristics from four donors were evaluated. Following this, washed sperm were acid extracted and proacrosin and acrosin activities determined spectrophotometrically. Proteinase activity in unactivated sperm extracts was then extracts was then demonstrated using the gelatin-SDS-PAGE system. Three major (Mr approximately equal to 47,000-54,000) and four faint (Mr approximately equal to 34,000-38,000) bands of digestion were observed. Upon activation of sperm extracts it was observed that maximum esterase activity occurred within 7 min of activation while maximum proteinase activity required approximately 15 min. When gels were washed and incubated in the presence of 50 mM benzamidine, no digestion bands were observed. This indicates that all of the digestion bands were due to trypsin-like proteinases. Finally, upon serial dilution of sperm extracts it was found that this SDS-PAGE system is sensitive enough to detect proteinase activity from as few as 30,000 sperm.
 ...
PMID:Evaluation of the human sperm proacrosin-acrosin system using gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophesis. 392 46

1. Proteinase inhibitors have been studied in whole serum by using a kinetic method that avoids potentially damaging protein separation procedures. 2. The alpha 2-macroglobulin of an individual can be allocated unambiguously into one of seven categories according to the binding of trypsin to inhibitor in two kinetically apparent binding modes (beta- and alpha-modes). 3. The distribution of alpha 2-macroglobulin beta:alpha ratios in a healthy adult population is defined, and shown to be independent of sex and age. 4. The distribution of beta:alpha ratios in a group of patients with cryptogenic fibrosing alveolitis was found to be significantly different (P less than 0.005) from the normal distribution. 5. Changes in the beta:alpha ratio were noted in five of six patients with cryptogenic fibrosing alveolitis after treatment, but on no occasion when two healthy subjects were assessed a total of nine times. 6. The molecular interpretation and the possible importance of altered proteinase inhibition in inflammation and fibrosis are discussed.
 ...
PMID:Different distributions of kinetically apparent molecular varieties of alpha 2-macroglobulin in health and in patients with cryptogenic fibrosing alveolitis. 616 12


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