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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The amino-acid sequence of a lectin isolated from the coelomic fluid of the acorn barnacle Megabalanus rosa has been determined. The lectin (Mr 140,000) is a multimeric protein whose subunit consists of 173 amino acids and one carbohydrate chain attached to Asn-39. The amino-acid sequence was determined by the manual sequencing of peptides derived from the protein by digestion with Staphylococcus aureus V8 proteinase, lysine endopeptidase and chymotrypsin, as well as fragments produced by cleavage with cyanogen bromide. The amino-acid sequence of the lectin was compared with the sequence of one (Mr 64,000) of the multiple lectins of M. rosa. They are distinct molecules in spite of a significant homology in their amino-acid sequences. The amino-acid sequence includes some regions homologous to those in other invertebrate lectins, such as sea urchin and flesh fly lectins, and vertebrate lectins. This is the first report to show the amino-acid sequence of multiple lectins isolated from an invertebrate.
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PMID:The amino-acid sequence of multiple lectins of the acorn barnacle Megabalanus rosa and its homology with animal lectins. 235

Human alpha 2-antiplasmin rapidly forms a stable, equimolar complex with either its target enzyme, plasmin, or with trypsin. Perturbation of the inhibitor-trypsin complex results in peptide bond cleavage at the reactive site of the inhibitor with the concomitant release of a small peptide fragment which apparently represents the carboxyl-terminal segment of the inhibitor. Sequence analysis of this fragment, together with that of an overlapping peptide obtained by treatment of native inhibitor with either Staphylococcus aureus V8 proteinase or human neutrophil elastase, yields data which indicate that the reactive site of alpha 2-antiplasmin encompasses a P1-P'1 Arg-Met sequence. However, unlike alpha 1-1-proteinase inhibitor which has a Met residue in the P1-position, oxidation of alpha 2-antiplasmin has no effect on its inhibitory activity toward either plasmin, trypsin, or chymotrypsin, indicating the lesser mechanistic importance of the P'1-residue during enzyme inactivation by this inhibitor.
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PMID:The reactive site of human alpha 2-antiplasmin. 243 12

Hexokinase (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) has been synthesized in the rabbit reticulocyte lysate system directed by poly(A)+ mRNA isolated from rat brain. Identification of the in vitro synthesis product as hexokinase was based on its immunoprecipitation with anti-hexokinase serum as well as the generation of identical peptide maps after partial cleavage of the in vitro product and authentic hexokinase with Staphylococcus aureus V8 proteinase or chymotrypsin. The in vitro product and authentic hexokinase were indistinguishable in molecular weight (SDS-gel electrophoresis); thus, despite the fact that, in situ, much of the hexokinase in brain is found in association with mitochondria, it is not synthesized in the form of a higher molecular weight precursor as is characteristic of other mitochondrial proteins. This is in accord with the view that hexokinase is best considered as a classical 'soluble' enzyme which is capable of exhibiting reversible association with mitochondria. The in vitro product cochromatographs (during anion-exchange HPLC) with authentic hexokinase previously shown to have a blocked (presumably acetylated) N-terminus; this procedure is capable of resolving the N-terminally blocked form of the enzyme from a partially proteolyzed form having a free N-terminal amino group. Thus the in vitro product is apparently N-acetylated by an enzyme system previously shown to be present in reticulocyte lysates. A significant fraction of the in vitro synthesized hexokinase attained a conformation characteristic of the native enzyme as judged by the observations that it could be immunoprecipitated by monoclonal antibodies recognizing the native enzyme but not by antibodies recognizing denatured hexokinase, and limited tryptic cleavage of the in vitro product gave fragments identical to those seen with the native enzyme and thought to reflect the organization of structural domains in that enzyme. However, based on these same criteria, the majority of the hexokinase synthesized in vitro appears to exist in a folding state that is not identical to that of either the fully denatured or native enzyme.
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PMID:In vitro synthesis of rat brain hexokinase. 286 81

We report the isolation from tomato (Lycopersicon esculentum) of an ethylene-responsive member of the proteinase inhibitor gene family. DNA sequence analysis of a full-length cDNA clone indicates that the ethylene-responsive gene is distantly related to the tomato proteinase inhibitor I gene, having 53% sequence identity. The predicted amino acid sequence reveals 47% and 45% sequence identity with the tomato and potato proteinase inhibitor I polypeptides, respectively. Additionally, the ethylene-responsive inhibitor has evolved a completely different pattern of gene expression and inhibitory specificity than other members of the inhibitor I family. Gel blot hybridization experiments show that, unlike the tomato proteinase inhibitor I gene, it is not induced in wounded leaves. In contrast, it is activated by the plant hormone ethylene in leaves and during fruit ripening. Furthermore, the ethylene-responsive inhibitor exhibits a novel reactive site, having glutamic acid as the P1 residue. This suggests that the ethylene-responsive proteinase inhibitor does not react with chymotrypsin, as does proteinase inhibitor I, but that it reacts with proteolytic enzymes that cleave at glutamic residues, such as the Staphylococcus aureus V8 proteinase, for which no inhibitors are known. Finally, isolation and analysis of a genomic clone reveals that the ethylene-responsive proteinase inhibitor gene is tightly linked to another, yet unidentified, coordinately expressed gene. We discuss these results with regard to the function and evolution of proteinase inhibitor genes in tomato.
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PMID:Ethylene-regulated expression of a tomato fruit ripening gene encoding a proteinase inhibitor I with a glutamic residue at the reactive site. 290 99

The primary structure of the Hypoderma lineatum collagenase was determined. Chymotrypsin digestion and thermolysin fragmentation of the chymotryptic core gave 30 and 5 peptides, respectively, accounting for all the residues of the protein. These peptides were aligned with overlapping peptides derived from tryptic and Staphylococcus aureus V8 proteinase digests. Hypoderma collagenase is a serine proteinase composed of 230 amino acids (Mr 25,223). It displays a high degree of sequential homology with the serine proteinases of the trypsin family, especially with another collagenolytic enzyme, the proteinase I of the crab Uca pugilator. The six half-cystinyl residues of Hypoderma collagenase correspond to 6 of the 10 half-cystinyl residues of chymotrypsin, and the residues forming the charge-relay system of the active site of chymotrypsin (His-57, Asp-102, and Ser-195) are found in corresponding regions. The prediction of the secondary structure of the collagenase is given.
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PMID:Complete amino acid sequence of the collagenase from the insect Hypoderma lineatum. 303 99

The capacity for self-polymerization and shape of the tubulin polymers assembled after digestion with trypsin, Pronase, chymotrypsin, subtilisin, Staphylococcus aureus proteinase V8 and proteinase K were investigated. Digestion with trypsin, Pronase or chymotrypsin resulted in a decrease in the ability of tubulin for self-assembly, whereas limited proteolysis with subtilisin, S. aureus proteinase V8 or proteinase K resulted in an increase in such ability. The shape of the assembled polymers varied from typical microtubules (after the treatment with trypsin or Pronase) to sheets (after the treatment with chymotrypsin) and from hooked microtubules with a constant polarity (after the treatment with subtilisin) to the disappearance of a defined polarity of such polymers (after the treatment with S. aureus V8 proteinase or proteinase K). These results indicate that the tubulin C-terminal regions are involved in the regulation of microtubule polymerization, shape, directional growth and lateral interactions between tubulin protofilaments.
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PMID:Effect of specific proteolytic cleavages on tubulin polymer formation. 304 48

A cytochrome P-450 (P-450SG1) was purified from a lanosterol 14 alpha-demethylase (P-450(14DM)) defective mutant of Saccharomyces cerevisiae, strain SG1, by a method similar to that used in the purification of the wild type enzyme (Yoshida, Y., and Aoyama, Y. (1984) J. Biol. Chem. 259, 1655-1660). P-450SG1 had the same apparent Mr as and was immunochemically identical to P-450(14DM). Peptide maps of P-450SG1 made by limited proteolysis with Staphylococcus aureus V8 proteinase, chymotrypsin, or papain followed by gel electrophoresis were identical to corresponding peptide maps of P-450(14DM). However, P-450SG1 showed no lanosterol 14 alpha-demethylase activity and its mode of interaction with diniconazole [(E)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-y1)-1- penten-3- o1], a specific inhibitor of P-450(14DM), was fundamentally different from that of P-450(14DM). The absorption spectrum of ferric P-450SG1 was unusual for a native low-spin cytochrome P-450 and was superimposable on that of 1-methylimidazole complex of P-450(14DM), indicating that P-450SG1 has a histidine 6th ligand trans to the thiolate 5th ligand, while the 6th ligand of other ferric low-spin cytochrome P-450s is a water molecule or a hydroxyl group of an oxyamino acid. It is concluded that P-450SG1 is an altered P-450(14DM). Difference in the primary structure between P-450SG1 and P-450(14DM) may be slight and was not detected by peptide mapping. However, the alteration caused significant change in the substrate site and heme environments of the cytochrome. P-450SG1 is the first example of a cytochrome P-450 having a histidine axial ligand trans to thiolate and of a genetically altered cytochrome P-450 isolated in a homogeneous state.
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PMID:Isolation and characterization of an altered cytochrome P-450 from a yeast mutant defective in lanosterol 14 alpha-demethylation. 311 90

The complete amino acid sequence of the p453-plasmid-mediated PIT-2 beta-lactamase (SHV-1) was determined. The protein contains 265 residues. Peptides resulting from digestions with trypsin, Staphylococcus aureus V8 proteinase, chymotrypsin and Lys-C proteinase and cleavage with CNBr were separated and purified by using reverse-phase h.p.l.c. The amino acid sequence of each peptide was manually determined with the dimethylaminoazobenzene isothiocyanate/phenyl isothiocyanate double-coupling method. The primary structure of PIT-2 beta-lactamase was compared with those of two closely related enzymes, namely TEM-1 beta-lactamase and the beta-lactamase of Klebsiella pneumoniae strain LEN-1. The PIT-2 beta-lactamase amino acid sequence was strongly retained, with respectively 68% and 88% homology. Thus PIT-2 enzyme could represent an evolutionary step between a chromosomally encoded beta-lactamase and the plasmid-mediated TEM beta-lactamases.
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PMID:Complete amino acid sequence of p453-plasmid-mediated PIT-2 beta-lactamase (SHV-1). 326 Apr 90

Antibodies were prepared against isolated rat renal glutaminase and affinity-purified against the 65 kDa peptide contained in the purified rat brain glutaminase. The affinity-purified IgGs were then used to compare the glutaminase immunoreactive peptides contained in samples that had been subjected to SDS/polyacrylamide-gel electrophoresis and transferred to nitrocellulose. The purified brain glutaminase and isolated brain mitochondria contain 68 and 65 kDa peptides that exhibit nearly equivalent immunostaining. Partial proteolysis of the isolated 68 and 65 kDa peptides with Staphylococcus aureus V8 proteinase produced an identical pattern of immunoreactive proteolytic fragments. However, digestion of the two peptides with chymotrypsin resulted in similar, but slightly different, patterns. The pattern of immunostaining was unaltered even when the brain mitochondria were solubilized with Triton X-100 and stored for 2 days at 4 degrees C. A very similar pattern was observed when intact renal mitochondria were subjected to immunoblot analysis. However, when renal mitochondria were solubilized, the 68 kDa peptide was rapidly degraded to the 65 kDa form. At 4 degrees C this reaction occurs with apparent first-order kinetics and a t1/2 of 35 min. Degradation of the 65 kDa form of the renal glutaminase occurs with much slower kinetics, but is nearly complete after 24 h. Solubilization of mitochondria isolated from various zones of the kidney indicated that the responsible endogenous proteinase was localized primarily in the cortex. Mitochondria isolated from intestinal or renal papillary tissue contain four glutaminase immunoreactive peptides (Mr 68,000, 65,000, 61,000 and 58,000). The smallest of these peptides is identical in size with the single immunoreactive peptide observed in liver tissue.
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PMID:Immunoblot analysis of glutaminase peptides in intact and solubilized mitochondria isolated from various rat tissues. 359 73

The hybrid glycophorin in Dantu-positive human erythrocytes of the N.E. variety was not cleaved by treatment of intact cells with various proteases, in contrast to normal glycophorins. Therefore, it could be purified by phenol/saline extraction of membranes from trypsin-treated and chymotrypsin-treated red cells and subsequent gel filtration in the presence of Ammonyx-LO. The complete structure of the hybrid molecule, comprising 99 amino acid residues, was elucidated by sequence analyses of peptides prepared by chymotrypsin, trypsin, cyanogen bromide or V8 proteinase treatment. The N-terminal 39 residues and the glycosylation of the molecule were found to be indistinguishable from those of blood-group-s-specific glycophorin B. Conversely, the residues 39-99 were shown to be identical with the residues 71-131 of the major blood-group M-active or N-active sialoglycoprotein (glycophorin A). Hemagglutination inhibition assays revealed that the Dantu antigen represents a labile structure. The receptor might be located within the residues approximately 28-40 of the hybrid glycophorin, as judged from the effects of modifications of membranes. Our data provide an explanation for the previous findings that Dantu-positive cells (N.E. type) exhibit a protease-resistant N antigen and a qualitatively altered s antigen.
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PMID:Hybrid glycophorins from human erythrocyte membranes. I. Isolation and complete structural analysis of the hybrid sialoglycoprotein from Dantu-positive red cells of the N.E. variety. 359 15


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