Alteration of Substrate Specificity and Optimum pH of Sarcosine Oxidase by Random and Site-Directed Mutagenesis.

The sarcosine oxidase gene was randomly mutated, and F103V, which showed altered specificity, was screened with the plate assay. Five different mutants at position 103 were also constructed. Each mutant exhibited a rather striking change in substrate specificity, except for F103W. The optimum pH was also shifted, depending on the substrate.