Molecular Pharmacology, Vol 12, 69-72, Copyright © 1976 by the American Society for Pharmacology and Experimental Therapeutics

N-Acetyltransferase of Brain: Some Properties of the Enzyme and the Identification of -Carboline Inhibitor Compounds

¹ Laboratory of Preclinical Pharmacology, National Institute of Mental Health, Saint Elizabeths Hospital, Washington, D. C. 20032

Several -carboline derivatives, such as harmane, harmol, 6-methoxyharman, and melatonin, inhibited the N-acetylation of tryptamine by brain N-acetyltransferase. The enzyme of brain was active toward several indole- and phenylethylamine substrates. In contrast to the enzyme of brain, the enzyme of pineal was not inhibited by harmaline and harman, and 3,4-dimethoxyphenylethylamine was a relatively poor substrate. -carboline inhibitors may be useful aids for studying the various N-acetyltransferases and for evaluating the physiological role of the brain enzyme.

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ACKNOWLEDGMENT We thank Jeffrey Rubenstein for his expert technical assistance.