Abstract

Aldehyde derivatives of the biogenic amines (e.g., serotonin, dopamine) were prepared enzymatically, purified, and used as substrates for aldehyde reductase (EC 1.1.1.2), an enzyme capable of reducing these deaminated derivatives. The enzyme was partially purified from rat brain tissue. Aldehyde reductase derived from brain tissue differed from alcohol dehydrogenase (EC 1.1.1.1) in cofactor specificity and was inhibited by low concentrations of barbiturates (i.e., pentobarbital). The presence of various functional groups on the parent phenylacetaldehyde or indoleacetaldehyde structures was shown to significantly affect the Michaelis constants (K_m, V_max) for aldehyde reductase. The relationship between Michaelis constants determined for aldehyde reductase and the final product of biogenic amine metabolism in rat brain is discussed.