Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.4.3 (phospholipase C)
 18,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thiol:protein-disulfide oxidoreductase catalyzes the GSH reduction of protein disulfides to sulfhydryls. Chromatography of solubilized hepatic microsomes on Mono Q yielded two peaks, Q-2 and Q-5, which contained all the thiol:protein-disulfide oxidoreductase activity. These were further purified by chromatofocusing giving specific activities of 14.4 and 45.9 nmol/mg of protein/min, respectively with purifications of 45.0- and 143.6-fold. Amino acids 1-18 of Q-5 were the same as previously reported for Thiol:protein-disulfide oxidoreductase (Edman, J. C., Ellis, L., Blacher, R. W., Roth, R. A., and Rutter, W. J. (1985) Nature 317, 267-270), except amino acid 1 was leucine instead of aspartate and amino acid 6 was asparagine instead of glutamate. The N-terminal amino acid sequence of Q-2 differed markedly from Q-5 but Q-2 showed 100% identity at amino acids 25-54, 258-269, 285-310, 347-350, 412-419, and 434-463 for the reported sequence of rat, hepatic, cytosolic phosphatidylinositol-specific phospholipase C form 1a (PLC) (Bennett, C. F., Balcarek, J. M., Varrichio, A., and Crooke, S. T. (1988) Nature 334, 268-270). PLC activity was found in the elution from the Mono Q column, but none was found in purified Q-2 or Q-5. Antibodies to Q-5 reacted with Q-2, but anti-Q-2 did not react with Q-5. Anti-Q-2 antibody showed immunoreactivity with 55- and 60-kDa microsomal proteins, whereas Q-5 antibody reacted with a number of microsomal proteins. Although Q-2 was immunoreactive with a polyclonal antibody to guinea pig, uterine cytosolic PLC, partially purified PLCs from rat liver cytosol did not react to this antibody. Our data would suggest that the published sequence for PLC form 1a may actually be the sequence for Q-2.
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PMID:Purification and characterization of a new isozyme of thiol:protein-disulfide oxidoreductase from rat hepatic microsomes. Relationship of this isozyme to cytosolic phosphatidylinositol-specific phospholipase C form 1A. 165 21

Proteins of the internal nuclear matrix from chicken liver were fractionated, by chromatographic procedures, in non denaturing conditions. At least two fractions were present with phosphatidylinositol-specific phospholipase C and three with thiol:protein-disulfide oxidoreductase activity. A 57kDa protein was isolated which copurified with both these activities. Partial amino acid sequences showed a high degree of homology with a cytosolic protein previously identified as a phospholipase C and with a microsomal protein identified as a thiol:protein-disulfide oxidoreductase. Our finding leaves the question still unanswered of the real function of this protein, which for the first time has been isolated from the nuclear matrix.
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PMID:Purification of a 57kDa nuclear matrix protein associated with thiol:protein-disulfide oxidoreductase and phospholipase C activities. 835 13