Inositol 1,4,5-triphosphate phosphatase activity in membranes isolated from amphibian skeletal muscle [corrected |
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| Authors: | X Sánchez M A Carrasco J Vergara C Hidalgo |
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| Affiliation: | Centro de Estudios Cientificos de Santiago, Casilla, Chile. |
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| Abstract: | The hydrolysis of [3H]inositol 1,4,5-trisphosphate by a soluble fraction and by isolated transverse tubule and sarcoplasmic reticulum membranes from frog skeletal muscle was studied. Transverse tubule membranes displayed rates of hydrolysis several-fold higher than those of sacroplasmic reticulum and soluble fraction; Km and Vmax were 25.2 microM and 44.1 nmol/mg/min, respectively. Transverse tubule membranes sequentially hydrolyzed inositol trisphosphate to inositol bisphosphate, inositol 1-phosphate and inositol, indicating that these membranes have inositol bis- and monophosphatases in addition to inositol trisphosphatase. |
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