Enzymic preparation and characterization of an α- l-β-methylaspartic acid

Charcoal-treated extracts of Clostridium tetanomorphum, incubated with mesaconate and an ammonium salt under suitable conditions, catalyze the formation of large amounts of a dicarboxylic amino acid which has been isolated and shown to be an α- l-β-methylaspartic acid. The compound has been tentatively identified as the l- threo isomer. A simple enzymic method is given for preparing 15 g. of the pure amino acid. A spectrophotometric method for the quantitative determination of enzymic β-methylaspartic acid in amounts of 0.02-0.25 μmole is described.