Production of aminoacetone by Rhodopseudomonas spheroides

Abstract

A non-acidic aminoketone accumulates when Rhodopseudomonas spheroides is incubated aerobically in the dark or anaerobically in the light in a medium containing ev-oxoglutarate, fumarate and glycine. Aerobically in the dark the accumulation is increased by the presence of Mn2+ in the medium. The aminoketone was purified and identified as aminoacetone. A L-threonine dehydrogenase which converts threonine into aminoacetone in the presence of NAD+ was detected in extracts of this organism. The enzyme was partially purified and its properties were studied. The enzyme will not utilize NADP+ in place of NAD+, and it is specific for the isomers of [alpha]-amino-[beta]-hydroxybutyric acid having the D-configuration on the [beta]-carbon atom. l-Aminopropan-2-ol is not an intermediate. A soluble [beta]-hydroxybutyrate dehydrogenase obtained from the same organism has also been studied.