The use of a sulfide ion selective electrode to study O-acetylserine sulfhydrylase from germinating rapeseed

O-Acetylserine sulfhydrylase was partially purified from germinating seeds of Rape (Brassica napus L. var Target), and a sulfide ion specific electrode used to study the properties of this enzyme. It was demonstrated that the sensitivity of the electrode to sulfide ion concentration was not affected by pH, or by various concentrations of cysteine, sulfate, sulfite, and acetate.Kinetic studies showed that the K_m for O-acetyl-l-serine was 1.74 × 10^?6m, while the K_m for sulfide was 4.3 × 10^?4m. The implications of the data, together with the methods used to obtain them, are discussed.