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THE DISTRIBUTION AND PROPERTIES OF THE NONSPECIFIC N ‐METHYLTRANSFERASE IN BRAIN
Author(s) -
Saavedra J. M.,
Coyle J. T.,
Axelrod J.
Publication year - 1973
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.1471-4159.1973.tb00035.x
Subject(s) - tryptamine , enzyme , chemistry , biochemistry , phenylethanolamine , cerebral cortex , methyltransferase , enzyme assay , distribution (mathematics) , specific activity , guinea pig , endocrinology , methylation , biology , tyrosine hydroxylase , mathematical analysis , mathematics , gene
— The distribution and properties of a nonspecific N ‐methyltransferase in the rat brain are described. The enzyme N ‐methylates tryptamine and N ‐methyltryptamine as well as β‐phenylethylamine, phenylethanolamine, tyramine and octopamine. The enzyme exhibits a pH optimum of 7·9 with phosphate buffer and has a K m for tryptamine of 28 μM. There are potent inhibitors to the enzyme that can be removed by dialysis. Enzymatic activity is present in the brains of a number of species including man, rat, mouse, guinea‐pig and frog. Its activity is unevenly distributed in the brain with the highest activity in the cerebral cortex and striaturn of the rat and in the subcortical white matter in man. Studies of its subcellular distribution indicate that most of the N ‐methylation activity is released into the soluble fraction. Enzymatic activity is also present in a number of peripheral tissues of the rat.