Oxalyl CoA synthetase, a key enzyme in the biosynthesis of β-oxalyl CoA synthetase, a key enzyme in the biosynthesis of days old seedlings of Lathyrus sativus using affinity chromatography and electroelution. The enzyme existed in three forms. They were designated as OCS-1, OCS-2 and OCS-3 and their molecular weights were found to be 63.1, 39.9 and 17.7 kDa, respectively. The antibodies were raised against all the three enzymes. The monospecificity of the antiserum was checked by immunoblotting. OCS-1 and OCS-2 did not share any common epltopes as no cross-reaction was seen. © 1992 Springer-Verlag.