L-threo-3,4-dihydroxyphenylserine (DOPS) aldolase: a new enzyme cleaving DOPS into protocatechualdehyde and glycine.

An enzyme which cleaves L-threo-3,4-dihydroxyphenylserine into protocatechualdehyde and glycine was demonstrated in extracts of human brains. Equimolar production of protocachualdehyde and glycine was quantitatively confirmed using high-performance liquid chromatography. In subcellular fractions of the brain, the highest enzyme activity was found in cytosol and soluble fraction. L-threo-DOPS proved to be the best substrate for this enzyme. The L-erythroisomer was less active and D-threo- and D-erythro-isomers were essentially inactive. The enzyme activity has an optimal pH around 7.4, and requires pyridoxal phosphate for maximal activity.