title: Identification of the amino acid bound to the labile adduct formed during inactivation of monoamine oxidase by 1-phenylcyclopropylamine.
abstract: Three reactions are carried out on the reversible adduct formed when 1-phenylcyclopropylamine (1-PCPA) inactivates monoamine oxidase (MAO) in order to determine the identity of the amino acid involved in reversible adduct formation. Raney nickel treatment yields trans-beta-methyl[14C]styrene, the compound that would result from carbon-sulfur bond reduction of a (3-hydroxy-3-phenyl-propyl)cysteine adduct. A 5,5'-dithiobis(2-nitrobenzoic acid) assay for cysteine residues indicates that upon reversible inactivation of MAO by 1-PCPA, one cysteine is lost. The third reaction involves sodium periodate and hydrogen peroxide oxidation, but no definitive result is obtained. The first two reactions provide evidence that the amino acid residue involved in reversible adduct formation is a cysteine.
mesh_terms: D001665:Binding Sites; D003521:Cyclopropanes / Q000378:metabolism* / Q000494:pharmacology; D003545:Cysteine / Q000378:metabolism; D008928:Mitochondria / Q000201:enzymology; D008995:Monoamine Oxidase / Q000378:metabolism*
chemical_list: D003521:Cyclopropanes; C045293:1-phenylcyclopropylamine; D008995:Monoamine Oxidase; D003545:Cysteine