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)

Fumarases in the mitochondrial and cytosolic fractions of rat liver were separately purified and crystallized. These two fumarases were not distinguishable in physicochemical, catalytic, or immunochemical properties. The sequences of seven amino acids in the C-terminal portions of the two fumarases were shown using carboxypeptidase P to be identical, i.e.-Val-Asp-Glu-Thr-Ala-Leu-Lys-. The amino acid sequence of the N-terminal portion of the mitochondrial fumarase was determined by the Edman method as Ala-Gln-Gln-Asn-Phe-Glu-Ile-Pro-Asp-, but that of the cytosolic fumarase could not be determined by the Edman method, since the N-terminal amino acid was blocked. The N-terminal amino acid of the cytosolic fumarase was identified as N-acetyl-alanine by analysis of the acidic amino acid produced by digestion of the enzyme protein with pronase E, carboxypeptidase A and B. Then the sequence of five amino acids in the N-terminal portion was determined by analyzing the acidic peptide obtained by limited proteolysis of the enzyme protein with carboxypeptidase A as Ac-Ala-Ser-Gln-Asn-Ser-. Peptide mapping of the tryptic peptides obtained from the mitochondrial and cytosolic fumarases showed no difference in the amino acid sequences of the two except in their N-terminal portions. The turnover rates of the mitochondrial and cytosolic fumarases were determined by injecting L-[U-14C]leucine into rat and following the decay of specific radioactivity incorporated into immunoprecipitates from the partially purified enzyme. The half-life of the cytosolic fumarase was estimated as 4.8 days from the decay curve of its specific radioactivity. The decay curve of the specific radioactivity of the mitochondrial fumarase, obtained after a single injection of L-[U-14]leucine, was quite unusual: its specific radioactivity remained constant for about 7 days after pulse labeling, and then decreased exponentially with a half-life of 9.7 days. Similar amounts of cytosolic and mitochondrial fumarase were found in the livers of the rat, mouse, rabbit, dog, chicken, snake, frog, and carp, respectively. Similar subcellular distributions of the enzyme were also found in the kidney, heart, and skeletal muscle of rats, and in hepatoma cells (AH-109A). However, in rat brain no fumarase activity was detected in the cytosolic fraction. Two putative precursor polypeptides of rat liver fumarase were synthesized when rat liver RNA was translated in vitro in a rabbit reticulocyte lysate system.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Mechanism of synthesis and localization of mitochondrial and cytosolic fumarases in rat liver. 381 85

The role of nitric oxide (NO) in precipitating pulmonary oedema in acute lung injury remains unclear. We have investigated the mechanism of involvement of NO in the maintenance of liquid balance in the isolated rabbit lung. Thirty pairs of lungs were perfused with colloid for up to 6 h, during which pulmonary vascular resistance (PVR) and capillary pressure (PCP) were measured frequently, and time to gain 5 g in weight (t5) was recorded. Four protocols with different perfusate additives were studied: (i) none (control, n = 11); (ii) 10 mmol NG-nitro-L-arginine methyl ester (L-NAME) (n = 6); (iii) 10 mmol L-NAME with 100 mumol lodoxamide, an inhibitor of mast cell degranulation (n = 7); (iv) 10 mmol L-NAME with 10 mumol 8-bromo-3',5'-cyclic guanosine monophosphate (8Br-cGMP), an analogue of cGMP that may reduce vascular permeability by relaxing contractile elements in endothelial cells (n = 6). Neither PVR nor PCP differed between protocols. L-NAME markedly reduced t5 from 248 (27) min (mean (SEM)) in protocol (i) to 144 (5) min in protocol (ii) (P < 0.05). Both lodoxamide (t5 = 178 (7) min) and 8Br-cGMP (t5 = 204 (10) min) substantially corrected the effect of L-NAME (P < 0.005). Results suggest that maintenance of a low permeability by NO may involve mast cell stabilization and endothelial cell relaxation.
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PMID:Inhibition of nitric oxide synthesis augments pulmonary oedema in isolated perfused rabbit lung. 1106 16