Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In patients exhibiting chronic alcohol abuse, the accumulation of fat droplets in pancreatic acinar cells, as well as changes in pancreatic secretion, can be interpreted as early signs of pancreatic damage. Using rats, (the animals were fed for 9 +/- 1 months with a solution of 20% v/v ethanol, combined with either a normal or a fat enhanced diet) we tested whether or not these symptoms are related both to each other and to morphological lesions of the tissue. Based on six separate histological criteria, the lesions were classified into five stages of severity. In order to characterize the secretory capacity of the pancreas, we measured the outputs of lipase, alpha-amylase, trypsin, chymotrypsin, carboxypeptidase A, elastase, and phospholipase A. Compared with the control group, we found that the alcohol-fed animals exhibited a significantly higher degree of morphological damage to the pancreas, as well as an increased frequency of fat accumulation in the acinar cells, and, with the exception of alpha-amylase, a rise in the level of enzyme secretion. In the animals exhibiting the highest degree of tissue damage, however, both fat accumulation and hypersecretion appeared to be diminished. This diminution could possibly be interpreted as the first sign of chronic pancreatitis. Increased consumption of fat did not change either the level of fat accumulation in the acinar cells, or the level of pancreatic secretion. Within the group of alcohol-fed rats, the most pronounced levels of hypersection were found in animals exhibiting cellular fat accumulation. However, the secretion levels of the alcohol-fed animals exhibiting no such fat accumulation did not differ significantly from that of the control group. Therefore, a relationship appears to exist in rats between fat accumulation in acinar cells and the level of pancreatic secretion.
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PMID:[Correlation between acinar cell fat accumulation and secretory capacity of the rat pancreas in the early stage of alcohol-induced pancreatopathy]. 163 69

A juvenile-hormone-binding protein (juvenile-hormone carrier), isolated from Galleria mellonella haemolymph, was treated with trypsin, chymotrypsin, carboxypeptidase A and subtilisin. Among these enzymes, only subtilisin was able to affect juvenile-hormone-binding activity of this protein. With SDS/PAGE it was shown that juvenile-hormone-binding protein, a 32-kDa peptide, is first slowly converted into a 30-kDa molecule, then into two or three smaller-molecular-mass species (20-25 kDa), which in turn were further digested to small peptides undetectable in PAGE. The 30-kDa peptide has a 2.4-times-higher dissociation constant for juvenile hormone than the native protein. No binding activity was detected for 20-25-kDa peptides. The rate of proteolysis of juvenile-hormone-binding protein was decreased by more than twofold in the presence of hormone, however, the overall cleavage pattern was unchanged. Under non-denaturing conditions, free binding-protein molecules could be separated from juvenile-hormone-binding-protein complex due to a slower electrophoretic mobility of the complex. As judged from ultracentrifugation and cross-linking experiments, binding of the hormone to its haemolymph carrier does not induce formation of oligomers, but shifts the sedimentation coefficient from 2.30S to 2.71S. It is concluded that juvenile-hormone binding induces a conformational transition of its carrier protein. This hormone-induced change might have a physiological significance for signal transmission.
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PMID:Conformational change of the haemolymph juvenile-hormone-binding protein from Galleria mellonella (L). 193 32

Cross-linking of 125I-IL-4 to the surface of cells expressing IL-4R yields as the major IL-4-binding molecules, polypeptide chains with inferred m.w. of approximately 70,000 (p70) and approximately 120,000 to 140,000 (p120-p140). The demonstration that the functional product of the IL-4R cDNA clone has m.w. of approximately 140,000 and that no p70 product is detected in transfected COS-7 cells has led to an uncertainty regarding the nature of p70. To study this issue, we examined the relationship of the IL-4-binding molecules p120 and p70 and, in parallel, attempted to immunoprecipitate p70 from surface and internally labeled cells using IL-4 and two anti-IL-4R antibodies (M1 and M2), bound to Affigel 10, as ligands. Cross-linked complexes containing 125I-IL-4 and p70 or p120 were isolated and digested with chymotrypsin or with V8 protease. Three distinct IL-4-binding peptides could be compared; these were indistinguishable for cross-linked p70 and p120, strongly implying that p70 and p120 were structurally related. Furthermore, immunoprecipitates made with IL-4 or anti-IL-4R-Affigel did not contain p70. This led us to conclude that p70 is a breakdown product of p120. A second IL-4-binding molecule of 40,000 Da (p40) expressing the M1 and M2 epitopes of the IL-4R was detected and appears to be the product of an mRNA coding for the soluble form of the receptor. mRNA for p40 was detected in both the T cell line CT.4R and the mast cell line CFTL.12 using polymerase chain reaction primers unique to this species of message. Pulse-chase studies of IL-4R in [35S] methionine-labeled cells indicates that p40 is derived from a 42,000-Da precursor that is detectable at the end of the pulse period, and thus, further argue that p40 is an independently translated molecule and not a degradation product of p120. Although p40 has been previously shown to be a soluble, truncated form of the receptor, we failed to observe secretion of p40 into the medium by internally labeled CT.4R cells.
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PMID:The IL-4 receptor: biochemical characterization of IL-4-binding molecules in a T cell line expressing large numbers of receptors. 200 96

Microproteins with proteinase inhibitory activity, 28 to 30 amino acids long, with 3 disulfide bridges have been isolated from Ecballium elaterium seeds. A peptide (EETI II) was isolated and behaved as a powerful trypsin inhibitor (Kd = 10(-11) to 10(-12) M). It was sequenced, chemically synthesized and the 3-D structure determined by 2-D 1H NMR. The information gained in the process enabled us to synthesize modified derivatives with inhibitory activity towards pancreatic elastase, chymotrypsin and human leucocyte elastase (Kd = 10(-7) to 10(-9) respectively). The most striking characteristic that appeared during the synthetic approach was the unfailing ability of the 28 amino acid peptides to refold and correctly close the 3 disulfide bridges, giving in each case an active compound. These disulfide bridges are assembled in a particular knotted structure, shared by few other bioactive peptides and called the 'knottin' structure. Molecular modeling of the peptide and a comparison with the other active molecules with similar topology allowed the synthesis of a chimaeric peptide, bearing 1 active site against a seryl-protease (trypsin), and 1 against a metallo-protease (carboxypeptidase A). The bis-headed peptide was able to inhibit both enzymes separately and concomitantly.
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PMID:Molecular recognition between serine proteases and new bioactive microproteins with a knotted structure. 212 46

Incubation of oat root plasma membrane vesicles in the presence of ATP with trypsin or chymotrypsin increased the rate of ATP hydrolysis and ATP-dependent proton pumping by the plasma membrane H(+)-ATPase. Proton pumping was stimulated more than 200%, whereas ATP hydrolytic activity was stimulated about 30%. The Km (ATP) for both proton pumping and ATP hydrolysis was lowered from about 0.3 mM to below 0.1 mM. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of trypsin-treated plasma membranes revealed a decrease in a 100-kDa band and the appearance of a 93-kDa band. Western blot analysis using antibodies against the H(+)-ATPase showed that both of these bands represented the H(+)-ATPase and suggested that a 7-kDa segment was released. Extensive treatment with carboxypeptidase A also activated the H(+)-ATPase indicating that the 7-kDa segment originated from the C terminus.
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PMID:Proteolytic activation of the plant plasma membrane H(+)-ATPase by removal of a terminal segment. 214 84

Hirudin, a thrombin-specific inhibitor, comprises a compact amino-terminal core domain (residues 1-52) and a disordered acidic carboxyl-terminal tail (residues 53-65). An array of core fragments were prepared from intact recombinant hirudin by deletion of various lengths of its carboxyl-terminal tail on selective enzymatic cleavage. Hir1-56 and Hir1-53 were produced by pepsin digestion at Phe56-Glu57 and Asp53-Gly54. Hir1-52 was generated by Asp-N cleavage at Asn52-Asp53. Hir1-49 was prepared by cleavage of Gln49-Ser50 by chymotrypsin, elastase, and thermolysin. In addition, Hir1-62 (containing part of the carboxyl-terminal tail) was derived from Hir1-65 by selective removal of the three carboxyl-terminal amino acids using carboxypeptidase A. Hirudin amino-terminal core fragments were stable at extreme pH (1.47 and 12.6), high temperature (95 degrees C), and resistant to attack by various proteinases. For instance, following 24-h incubation with an equal weight of pepsin, the covalent structure of Hir1-52 remained intact and its anticoagulant activity unaffected. Unlike intact hirudin (Hir1-65) the inhibitory potency of which is a consequence of concerted binding of its amino-terminal and carboxyl-terminal domains to the active site and the fibrinogen recognition site of thrombin, the core fragments block only the active site of thrombin with binding constants of 19 nM (Hir1-56), 35 nM (Hir1-52), and 72 nM (Hir1-49). As an anticoagulant Hir1-56 is about 2-, 4-, and 30-fold more potent (on a molar basis) than Hir1-52, Hir1-49, and Hir1-43, respectively. Hir1-56 was also about 15-fold more effective than the most potent carboxyl-terminal fragment of hirudin, sulfated-Hir54-65, although they bind to independent sites on thrombin. The potential advantages of hirudin core fragments as antithrombotic agents are discussed in this report.
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PMID:Production, properties, and thrombin inhibitory mechanism of hirudin amino-terminal core fragments. 226 19

The protease inhibitor alpha-1-antichymotrypsin, which binds to chymotrypsin-like enzymes in a sodium dodecyl sulfate-resistant manner, has been shown recently to be both a normal constituent of brain and an integral component of the neuritic plaques that form in Down's syndrome and Alzheimer's disease. We have now identified in rat brain a Mr 25,000 alpha-1-antichymotrypsin-binding protein classified as a chymotrypsin-like protease by its inhibitor profile and substrate specificity. Release of 125I-labeled breakdown products from bands containing the protease in substrate-linked polyacrylamide gels was examined in parallel with hydrolysis of tetrapeptide chromogenic substrates in vitro to establish conditions under which the Mr 25,000 protease was the only activity being measured in vitro. The protease was completely membrane associated but was extractable using 1 M MgCl2; prior extraction of detergent- and low ionic strength-soluble proteins from membranes was used to increase its specific activity. The formation of sodium dodecyl sulfate-resistant bonds between human alpha-1-antichymotrypsin and the protease (kassoc = 2.9 X 10(6) M-1 s-1) was used to titrate the concentration of free protease solubilized from membranes. The protease cleaved both succinyl-Ala-Ala-Pro-Phe-p-nitroanilide, and methoxy-succinyl-Ala-Ala-Pro-Met-p-nitroanilide, the latter being of interest because cleavage after a methionine residue is predicted to generate the amino terminus of the neuritic plaque component beta-amyloid from its precursor protein. In fact, the solubilized protease degraded 90% of membrane-associated beta-amyloid precursor protein detected by Western blot analysis. The protease was kinetically distinct from both chymotrypsin and cathepsin G in direct comparisons and did not match kinetic values published for the rat mast cell proteases against comparable substrates; we therefore refer to the protease with the descriptive acronym clipsin (for chymotrypsin-like protease). Proteases similar to and potentially identical to clipsin were detected by enzymography in other organs from rat (most notably spleen and adult lung). The enzyme in brain was distinguished by a narrow window of elevated activity surrounding postnatal day 5, which was 12-14-fold higher than levels in day 1 or adult brain. Because independent lines of evidence suggest that a brain chymotrypsin-like protease may be involved in the etiology of Down's syndrome and Alzheimer's disease, clipsin is discussed as a candidate for such a role.
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PMID:Clipsin, a chymotrypsin-like protease in rat brain which is irreversibly inhibited by alpha-1-antichymotrypsin. 230 81

The interaction of mouse intestinal mast cell proteinase (IMCP) with serine proteinase inhibitors (serpins) in blood was analysed: (i) by examining the capacity of the inhibitors in blood to block the binding of the irreversible serine esterase inhibitor [3H]diisopropyl fluorophosphate (DFP); (ii) by Western blotting. The binding of [3H]DFP to IMCP was blocked very rapidly by inhibitors in mouse serum and, by Western blotting, this inhibition was associated with the appearance of a 73,000 MW proteinase/inhibitor complex together with a series of higher (greater than 100,000) MW complexes. IMCP was not dissociated from these complexes when electrophoresed under reducing conditions, although prior heat treatment of mouse serum (60 for 30-160 min) abolished the formation of all proteinase/inhibitor complexes. Similarly, the activity of a 48,000 MW inhibitor of chymotrypsin was abolished by heat treatment. A titration experiment established that between 0.5 and 5 mg IMCP were inhibited per ml of serum. The properties and MW of the IMCP inhibitor complexes are typical of serpins and suggest that IMCP secreted during intestinal immunological reactions would be rapidly and irreversibly inactivated by plasma-derived inhibitors.
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PMID:Interaction of murine intestinal mast cell proteinase with inhibitors (serpins) in blood; analysis by SDS-PAGE and western blotting. 231 50

The structure of serine carboxypeptidase II from wheat bran has been determined to 3.5-A resolution by multiple isomorphous replacement, solvent flattening, and crystallographic refinement. The amino acid sequence has been fit to the electron density map and the model refined to a conventional crystallographic R factor of 20.9%. The molecule is an alpha + beta protein and contains a "catalytic triad" (Asp338, His397, and Ser146) similar in arrangement to those in chymotrypsin and subtilisin. The -fold of the polypeptide backbone is, however, completely different from those enzymes. This suggests that this is a third example of convergent evolution to a common enzymatic mechanism. The -fold is, on the other hand, surprisingly similar to that of the zinc proteinase carboxypeptidase A.
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PMID:Structure of wheat serine carboxypeptidase II at 3.5-A resolution. A new class of serine proteinase. 232 88

In inside-out red cell membrane vesicles active calcium transport and the formation of the enzyme-phosphate complex (EP) of the calcium pump were simultaneously investigated and the effects of a limited proteolytic digestion examined. In order to visualize the proteolyzed EP forms we have induced the formation of a maximum level EP from [gamma-32P]ATP in the presence of Ca2+ + La3+ and applied a good-resolution acidic discontinuous sodium dodecyl sulfate-polyacrylamide gel electrophoresis system. Proteolysis of inside-out vesicle membranes by trypsin, Pronase, papain, or chymotrypsin produces a calmodulin-like activation of the calcium pump, abolishes its calmodulin sensitivity, and decreases the original 140-kDa EP complex to a limit polypeptide of 80 kDa. Trypsin digestion produces another major intermediary fragment of 90 kDa, which is still a low-activity calmodulin-sensitive form of the pump. The red cell calcium pump is activated by trypsin both in the absence and presence of Ca2+ during digestion although the rate of activation and the appearance of the 80-kDa polypeptide are enhanced by Ca2+. If proteolytic digestion is carried out by chymotrypsin, a calmodulin-insensitive maximum activation of the calcium pump coincides with the formation of a 125-130-kDa EP-forming polypeptide. Chymotrypsin and carboxypeptidase A have synergistic effects on the formation of this latter high-activity species. Based on these data we suggest a probable molecular arrangement for the functional parts of the red cell membrane calcium pump.
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PMID:Molecular characterization of the in situ red cell membrane calcium pump by limited proteolysis. 242 14


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