Inability of low thymine-requiring mutants of Escherichia coli lacking phosphodeoxyribomutase to be induced for deoxythymidine phosphorylase and deoxyriboaldolase.

In a previous communication (T.R. Breitman and R. M. Bradford, Biochim. Biophys. Acta 138:217, 1967), we reported that Escherichia coli 70V3, a low thymine-requiring mutant of Escherichia coli 15, lacked deoxyriboaldolase activity, establishing a biochemical basis for the low requirement. Also presented were data indicating that both deoxythymidine phosphorylase and deoxyriboaldolase were induced coordinately when E. coli was grown on deoxythymidine. We suggested that deoxyribose 5-phosphate (dR-5-P) was more directly involved with these inductions than was deoxyribose 1-phosphate (dR-1-P), the compound implicated by W. E. Razzell and P. Casshyap