STUDY OF THE PURINE METABOLISM OFSTAPHYLOCOCCUS AUREUS

Publisher Website
Google Scholar
Abstract
The utilization of purines by 2 related strains of S. aureus was investigated. The parent wild-type strain (1-A) incorporates Cl4-labeled adenine, guanine, and hypo-xanthine into its nucleic acid purines. This strain can convert guanine to polynucleotide adenine, but is incapable of converting adenine to guanine. Since hypoxanthine-8-C14 is incorporated into guanine, the inability of strain 1-A to convert adenine to guanine appears due to a metabolic block between adenine and hypoxanthine. Strain 1-ACR (chloramphenicol resistant) requires adenine together with either hypoxanthine, xanthine, or guanine for growth. This strain incorporates labeled adenine and guanine only into its corresponding nucleic acid purine; it cannot interconvert adenine and guanine. Since relative specific activities of only 37 for adenine and about 55 for guanine are obtained, some form of cellular synthesis of purines de novo may be occurring to account for these low values. The metabolism of 2,6-diaminopurine was also investigated. It contributes principally to nucleic acid guanine in both strains. Diaminopurine inhibits the growth of strain 1-ACR when guanine or hypoxanthine (plus adenine) are proffered. Growth is restored completely when the nucleosides or nucleotides of guanine or hypoxanthine are supplied instead. Diaminopurine also inhibits the incorporation of labeled guanine by this strain. It is concluded that diaminopurine interferes with the nucleoside phosphorylase activity of strain 1-ACR. Diaminopurine has no effect on the incorporation of guanine-8-C14 by strain 1-A. This may mean that this strain does not utilize its exogenous guanine via nucleoside phosphorylase. It may use nucleotide pyrophosphorylase instead.