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Multiple Forms of Choline‐ O ‐Acetyltransferase in Mouse and Rat Brain: Solubilization and Characterization
Author(s) -
Benishin Christina G.,
Carroll Paul T.
Publication year - 1983
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.1471-4159.1983.tb09047.x
Subject(s) - choline acetyltransferase , chemistry , biochemistry , choline , cerebellum , triton x 100 , solubilization , sodium , chromatography , biology , acetylcholine , pulmonary surfactant , endocrinology , organic chemistry
Three forms of acetyl coenzyme A: choline‐ O ‐acetyltransferase (EC 2.3.1.6, ChAT) have been isolated from mouse and rat forebrain synaptosomes with a 100 m M sodium phosphate (NaP) buffer of pH 7.4, a high‐salt solution (500 m M NaCl), and a 2% Triton DN‐65 solution, respectively. The Triton‐solubilized form of ChAT differed from the other two forms in its capacity to acetylate homocholine, its pH profile, and its sensitivity to denaturation. NaCl‐solubilized ChAT could be distinguished from the other two forms with respect to pH profile, sensitivity to inhibition by 4–(1‐naphthylvinyl) pyridine (in the presence of Triton), and apparent K m value for choline acetylation. The caudate and putamen of rat brain contained the highest amount of ChAT activity, based on tissue wet weight, and the cerebellum contained the least of the brain regions examined; only the cerebellum had more membrane‐bound than soluble ChAT. Septal lesion reduced ChAT activity in the NaP‐ and Triton‐solubilized fractions prepared from hippocampus by 68% and 64%, respectively, whereas it reduced the activity of the NaCl‐solubilized fraction by only 21%. These results suggest that three different forms of ChAT may exist in both mouse and rat brain.