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PHOSPHOLIPASE ACTIVITY IN SQUID AND FROG AXONS
Author(s) -
Eyrich T. L.,
Bakrett D.,
Rock P. A.
Publication year - 1976
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1976.tb06989.x
Subject(s) - squid , choline , enzyme , calcium , phospholipase , chemistry , enzyme assay , sciatic nerve , phospholipase c , chromatography , biochemistry , biophysics , biology , anatomy , fishery , organic chemistry
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‐ 14 C]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‐CaCl 2 (aq); a K m 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 .