The enzymic degradation of L-serine O-sulphate. Mechanism of the reaction.

1. During the enzyme-catalysed degradation of l-serine O-sulphate no exchange occurs between the hydrogen atom attached to the alpha-carbon atom of the substrate and the tritiated water of the incubation medium. 2. The participation of an intermediate carbanion has been demonstrated in the degradation by performing the reaction in the presence of tetranitromethane. 3. Photo-oxidation of the enzyme in the presence of Rose Bengal led to a rapid inactivation of enzyme with the concomitant loss of four histidine residues/molecule. 4. Rose Bengal was also a non-competitive inhibitor of the enzyme.