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Acetylcholine Synthesizing Enzymes in Frog Skeletal Muscle
Author(s) -
Molenaar P. C.,
Polak R. L.
Publication year - 1980
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.1471-4159.1980.tb07855.x
Subject(s) - acetylcholine , denervation , choline , choline acetyltransferase , enzyme , chemistry , sartorius muscle , enzyme assay , cholinergic , biochemistry , medicine , endocrinology , biology , biophysics
Acetylcholine synthesis in homogenates of frog sartorius muscle was measured by a radiometric method with a low blank. Choline acetyltransferase activity was very low (V max , 2 nmol g 1 h −1 , K m for choline, approx. 50 μ , m ). The enzyme was found only in the endplate area and disappeared after denervation; it was inactivated by 4‐(1‐naphthylvinyl)pyridine. At high substrate concentrations its activity was overshadowed by the acetylcholine‐synthesizing activity of a different enzyme not saturated by 10 m m ‐choline. The non‐specific enzyme was present at and away from the endplate area, and it was not affected by denervation.