Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Granules that are potently cytolytic in vitro can be obtained from cytotoxic lymphocytes that kill virally infected cells and tumor cells. These granules contain pore-forming proteins and several serine proteases. Here we indicate that at least two different proteases participate in the lysis mediated by granule proteins from RNK-16 rat leukemia cells. We report twelve different mechanism-based or "suicide" isocoumarin serine protease inhibitors which have different 3- and 7-substituents that confer selectivity and reactivity towards either the chymotrypsin- ("chymase") or trypsin-like ("tryptase") protease activities of RNK-16 cells. Second order inhibition rates of inactivation (kobsd/[I]) for the RNK-16 granule proteases ranged between 164 and 22,640 M-1s-1. These new, specific and highly reactive isocoumarin serine protease inhibitors also abrogated the cytolysis mediated by lymphocytes granule proteins. The eight inhibitors with large hydrophobic or basic substituents that conferred chymase or tryptase specificities were more effective at inactivating lytic function than the four elastase-directed inhibitors with smaller substituents. All twelve new isocoumarin inhibitors blocked cytolysis at lower concentrations than 3,4-dichloroisocoumarin, a potent general mechanism-based serine protease inhibitor that also blocks RNK-16 granule protease activities and lysis.
Mol Immunol 1989 Aug
PMID:Selective isocoumarin serine protease inhibitors block RNK-16 lymphocyte granule-mediated cytolysis. 281 73

Refinement of the structure of gamma-chymotrypsin based on X-ray crystallographic data to 1.6-A resolution has confirmed the overall conformation of the molecule as reported previously [Cohen, G. H., Silverton, E. W., & Davies, D. R. (1981) J. Mol. Biol. 148, 449-479]. In addition, the new refinement suggests that gamma-chymotrypsin, which is operationally defined by its crystalline habit, may not be the free enzyme but rather a complex, possibly an acyl-enzyme adduct, with the tetrapeptide Pro-Gly-Ala-Tyr (or a close homologue). The crystallographic refinement provides a detailed geometrical description of the enzyme-substrate-solvent interactions that occur in the presumptive adduct.
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PMID:Is gamma-chymotrypsin a tetrapeptide acyl-enzyme adduct of alpha-chymotrypsin? 281 46

We have reported that the secretion of at least 17 distinct peptides [including rat (rGH)] GH by cultured rat pituitary cells was stimulated by GH-releasing hormone and inhibited by somatostatin, when analyzed by two-dimensional polyacrylamide gel electrophoresis. Three of these peptides (no. 23, 24, and 25) were not rGH immunoreactive. In order to determine whether these three peptides are fragments, degradation products or posttranscriptionally modified forms of rGH, rGH and peptide no. 23 were characterized structurally. From partial peptide maps of rGH and peptide no. 23 by V8 protease or chymotrypsin, it appeared that these peptides were not related to each other. By N-terminal microsequencing of two-dimensional polyacrylamide gel electrophoresis purified peptide, we have obtained the sequence of 24 N-terminal amino acid residues of peptide no. 23. This sequence has no significant homology with rGH or any other reported protein sequence. Antiserum was generated against a synthetic oligopeptide corresponding to amino acid residues 3-24 of peptide no. 23. The antiserum cross-reacted with peptides no. 23, 24, and 25 upon Western blot analysis. These results indicate that peptide no. 23 has a novel structure unrelated to other pituitary hormones. Since its secretion is influenced by GH-releasing hormone and somatostatin, peptide no. 23 may represent a previously unrecognized structurally unique growth factor.
Mol Endocrinol 1988 Oct
PMID:Growth hormone-releasing hormone stimulates and somatostatin inhibits the release of a novel protein by cultured rat pituitary cells. 290 40

We have measured the effects on catabolite gene activator protein (CAP) of 22 synthetic analogs of cAMP. Each analog was assayed to test three parameters: (1) binding to CAP; (2) induction of the conformational change in CAP; and (3) activation of transcription. Thus we have identified seven cAMP analogs that bind to CAP as well or better than does cAMP, cause the assayed conformational change in CAP, yet exhibit no ability to activate transcription. We designate these analogs class D. The conformational change elicited in CAP by the class D analogs was further investigated by: (1) sensitivity to the proteolytic enzymes chymotrypsin, Staphylococcus aureus V8 protease, subtilisin and trypsin; (2) formation of inter-subunit covalent crosslinks by 5,5'-dithiobis(2-nitrobenzoic acid); and (3) degree of labeling of cysteine by [3H]N-ethylmaleimide. These experiments failed to detect a conformational difference between the CAP-class D and CAP-cAMP complexes. Filter binding and nuclease protection experiments indicate that the class D analogs do not efficiently support the binding of CAP to DNA. From these results, we suggest that there exists a hitherto undetected event dependent on cAMP, and required for CAP to bind to DNA. We suggest that this event involves a change that takes place in proximity to the N6 atom of cAMP. Three possible interpretations are discussed.
J Mol Biol 1985 Mar 05
PMID:Analogs of cyclic AMP that elicit the biochemically defined conformational change in catabolite gene activator protein (CAP) but do not stimulate binding to DNA. 298 11

Guinea pig lung membrane leukotriene D4 (LTD4) receptors were prelabeled with [3H]LTD4 and solubilized using digitonin, 3-[(3-cholamidopropyl)- dimethylammonio]-1-propane sulfonate, and other non-ionic, zwitterionic, and ionic detergents. [3H]LTD4 remains tightly associated with the receptor complex in the digitonin solubilized state. The dissociation rate of [3]LTD4 from the soluble receptor complex was increased in the presence of guanine nucleotides and sodium ions in a manner similar to that observed for the receptors in the membrane-bound state. The soluble [3H]LTD4 receptor complex was retained on wheat germ lectin affinity columns and destabilized by heat (40 +/- 4 degrees), trypsin, and chymotrypsin treatment, suggesting that the receptor is a glycoprotein. Size exclusion high pressure liquid chromatography of the soluble receptor complex showed that an apparent molecular weight of the soluble receptor complex, in the presence of digitonin, is in the range of 240,000-500,000. An approximately 20-fold enrichment of receptor-radioligand complex was achieved by passing the solubilized LTD4 receptor preparation successively through size exclusion and wheat germ lectin chromatography columns. These data provide the first step toward the purification and chemical characterization of LTD4 receptors.
Mol Pharmacol 1986 Mar
PMID:Solubilization of [3H]leukotriene D4 receptor complex from guinea pig lung membranes. 300 31

Streptomyces griseus trypsin (SGT) is a bacterial serine proteinase that is more homologous to mammalian than to other bacterial enzymes. The structure of SGT has been solved primarily by molecular replacement, though some low-resolution phase information was supplied by heavy-atom derivatives. The mammalian pancreatic serine proteinases bovine trypsin (BT) and alpha-chymotrypsin (CHT) were used as molecular replacement models. Because these proteins have low homology with SGT compared to the majority of other successful replacement models, new strategies were required for molecular replacement to succeed. The model of SGT has been refined at 1.7 A resolution to a final R-factor of 0.161 (1 A = 0.1 nm); the correlation coefficient between all observed and calculated structure factor amplitudes is 0.908. Solvent molecules located in the crystal structure play an important role in stabilizing buried charged and polar groups. An additional contribution to stability can be seen in the fact that the majority of the charged side-chains are involved in ionic interactions, sometimes linking the two domains of SGT. A comparison of SGT with BT shows that the greatest similarities are in the active-site and substrate-binding regions, consistent with their similar substrate specificities. The modeling of complexes of SGT with two inhibitors of BT, pancreatic trypsin inhibitor (PTI) and the third domain of Japanese quail ovomucoid (OMJPQ3), helps to explain why PTI inhibits SGT but OMJPQ3 does not. Like BT, but unlike other bacterial serine proteinases of known structure, SGT has a buried N terminus. SGT has also a well-defined Ca2+-binding site, but this site differs in location from that of BT.
J Mol Biol 1988 Apr 05
PMID:Refined crystal structure of Streptomyces griseus trypsin at 1.7 A resolution. 313 12

Plasminogen Activator (PA) and its response to glucocorticoids and androgens was studied in viable rat thymocytes in suspension. PA was measured by its ability to convert plasminogen to plasmin, and the formed plasmin determined by cleavage of 14C-labeled globin. Using this functional assay, PA was found to be associated with the outer surface of thymic cells, and only negligible activity recovered from the incubation medium. Rat thymocytes also contain cytoplasmic and nuclear inhibitor(s) of the serine proteases plasmin, trypsin, chymotrypsin and thymic PA. Release of these inhibitors prevented determination of thymic PA activity in presence of lysed cells. The specific activity of PA in thymocytes isolated from adrenalectomized-castrated rats did not differ significantly from the specific activity associated with cells from intact animals. Furthermore, treatment of adrenalectomized-castrated rats with 0.1 mg of dexamethasone/kg for 2 days induced thymic involution without affecting thymic PA activity. These observations suggest that PA activity of thymocytes is not involved in glucocorticoid-mediated thymic involution.
Mol Cell Biochem 1985 Mar
PMID:Plasminogen activator and protease inhibitor activities in isolated rat thymocytes. 315 48

Using limited chymotrypsin and trypsin digestion of isolated Physarum histone H1 labeled in vivo in postsynthetically added N epsilon-methyl groups of lysine we show that: --there is no postsynthetic methylation in the central globular domain of H1, --a moderate number of methylated sites occurs in the N-terminal fragment and the part of the C-terminal fragment directly adjacent to the globular domain (the main site of interphase phosphorylation), --the most intensively methylated region occurs within the sequence located in an extended part of the C-terminal fragment, distant to the globular domain and the main site of interphase phosphorylation.
Mol Biol Rep 1988
PMID:Distribution of postsynthetic methylation sites in Physarum histone H1. 322 47

Mast cell proteinases are known to be released in response to helminth infection, and are, in particular, characteristic of the immune rejection of intestinal nematode parasites. In intestinal mucosal tissue the relevant enzyme is rat mast cell proteinase II (RMCP II) and that of other tissues, including the lung, is rat mast cell proteinase I (RMCP I). The function of these enzymes is unknown, and we have examined the possibility that they directly attack the parasites. This was done by examining the cleavage patterns produced by both proteinases on 125I-labelled excretory/secretory (ES) products of two intestinal nematodes (the infective larva of Ascaris suum, and adult Nippostrongylus brasiliensis) and one which has a pulmonary migration route (the third/fourth stage larva of A. suum). It was first established that all the labelled molecules were proteinaceous, by their susceptibility to broad spectrum proteinases, and that none were host components carried over into culture, by their antigenicity to infected hosts. All the nematode ES products were found to be remarkably resistant to RMCP I and II, only one major component of the infective larva of A. suum being cleaved by both enzymes. This was not found to reflect a resistance to serine proteinases in general, since selected ES components were cleaved by chymotrypsin and trypsin. This would, therefore, argue that, if the enzymes play any direct role in the immune expulsion of nematodes, it is unlikely to be successfully directed at their secretions.
Mol Biochem Parasitol 1987 Jun
PMID:Resistance of nematode secretory products to cleavage by mast cell proteinases. 330 71

The thiol-specific photoactivatable reagent 4-(2-iodoacetamido)benzophenone (BPIA) can be selectively incorporated into the SH-1 of myosin subfragment 1 (S1), and upon photolysis an intramolecular cross-link is formed between SH-1 and the N-terminal 25-kDa region of S1. If a Mg2+-nucleotide is present during photolysis, cross-links can be formed either with the 25-kDa or with the central 50-kDa region [Lu, R. C., Moo, L., & Wong, A. G. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 6392-6396]. Heavy chains with these two types of intramolecular cross-links and un-cross-linked heavy chain have different mobility on sodium dodecyl sulfate (NaDodSO4)-polyacrylamide gels and therefore can be purified electrophoretically. Each type of heavy chain was cleaved with Staphylococcus aureus protease, chymotrypsin, or lysyl endopeptidase. The cleavage points were determined on the basis of the molecular weights of weights of peptides containing the N-terminus, which was identified with the use of an antibody. Locations of the cross-links were deduced by comparing the peptide maps of cross-linked and un-cross-linked heavy chains. The results indicate that the segment located about 12-16 kDa from the N-terminus of the heavy chain can be cross-linked to SH-1 via BPIA independently of the presence of a nucleotide, whereas the segment located 57-60 kDa from the N-terminus can be cross-linked to SH-1 only in the presence of a Mg2+-nucleotide. With use of the avidin-biotin system, it has been shown that SH-1 is located 13 nm from the head/rod junction [Sutoh, K., Yamamoto, K., & Wakabayashi, T. (1984) J. Mol. Biol. 178, 323-339]. Since BPIA spans less than 1 nm, our results show that two regions, separated by approximately 400 amino acid residues and located in the 25- and 50-kDa domains of S1, respectively, are also part of the head structure about 12-14 nm from the head/rod junction.
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PMID:Identification of two segments, separated by approximately 45 kilodaltons, of the myosin subfragment 1 heavy chain that can be cross-linked to the SH-1 thiol. 331 Nov 49


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