Genetic Control of Metabolism of the Mutagenic Base Analog 6-N-Hydroxylaminopurine in Yeast Saccharomyces cerevisiae

Yeasts were shown to utilize 6-substituted adenine analogs as a purine source via the reutilization pathway leading to the formation of inosine monophosphate (IMP). This occurs because the ade12 strains with blocked conversion of IMP into adenosine monophosphate (AMP) cannot grow on media containing the above analogs as a sole purine source. Haploid strains with the double mutation ham1ade2 or ham1ade5 were also incapable of growing on a medium with 6-N-hydroxylaminopurine (HAP) as a sole purine source. However, in this case, the inability was caused by the occurrence of recessive lethal mutations rather than by a defect in purine reutilization. Yeast adenine aminohydrolase (AAH) can deaminate HAP to hypoxanthine. Adenine aminohydrolase (AAH) was uniformly active both in strains with a mutation in the HAMJ gene and in strains wild-type with respect to this trait.