PHOSPHOLIPASE ACTIVITY IN SQUID AND FROG AXONS |
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| Authors: | T. L. Eyrich D. Bakrett P. A. Rock |
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| Affiliation: | Merced Junior College, Merced, CA 95340, U.S.A.;Department of Biological Sciences, University of Denver. Denver, CO 80210. U.S.A.;The Department of Chemistry, University of California, Davis, CA 95616, U.S.A |
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| Abstract: | Evidence for the presence of phosphatide acylhydrolase activity (EC 3.1.1) in centrifuged homogenate supernatants and extracts of squid giant axons and centrifuged homogenate supernatants of frog sciatic nerve bundles is reported. The enzyme was assayed by measurement of the rate of deacylation of [U-14C]phosphatidyl choline. The deacylation activity in the nerve homogenate supernatants exhibits: a pH maximum at 7.2–7.4 (25°C); a calcium ion maximum at 12–13 mM-CaCl2(aq); a Km value of 3.4 × 10?4 M (25°C); and a temperature maximum at 37°C. The activation energy over the range 8–37°C is 5.7 ± 0.2kcal-mol?1. |
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