Abstract β-Cyano-l-alanine synthase was purified ca 1000-fold to homogeneity from the immature seeds of Vicia angustifolia. The purified enzyme has an apparent M r of 54 000 consisting of two identical subunits. The subunits contain one molecule of pyridoxal 5′- phosphate each. The K m value is 3.6 mM for l-cysteine and 0.5 mM for cyanide. β-Cyano-l- alanine synthase from V. angustifolia also catalyses the formation of some S-substituted l- ...
