Synthesis of Purine Intermediates by a Cell-free Extract of Escherichia Coli Samuel

A purine-requiring mutant (strain W-11) of Escherichia coli strain K-12, has been shown to synthesize 5-aminoimidazole riboside precursors (Love and Gots, 1955). This strain was thought to lack the enzymes responsible for the conversion of aminoimidazole ribotide to purines. On the basis of information on the biosynthesis of purines carried out with enzyme systems from pigeon liver (Buchanan et al., 1955), an attempt was made to synthesize the ribotide of aminoimidazole with extracts of this mutant. It was found that under proper experimental conditions these extracts carried out reactions directed toward the biosynthesis of purines or purine intermediates. The product of the reaction was, however, 5-amino4-imidazolecarboxamide ribotide rather than 5-aminoimidazole ribotide.