The assimilation of amino acids by bacteria. 22. The effect of 8-azaguanine upon enzyme formation in Staphylococcus aureus

Abstract

Formation of [beta]-galactosidase and catalase by washed suspensions of S. aureus Dunn is inhibited by the purine analogue, 8-azaguanine. Inhibition is observed when the analogue is added during the course of enzyme formation subsequent to induction. Addition of 8-azaquanine does not diminish nucleic acid synthesis by washed suspensions of S. aureus, as measured by the incorporation of (C14)-labeled uracil, but the analogue becomes incorporated into the cellular ribonucleic acid (RNA). Formation of [beta]-galactosidase, and of catalase in S. aureus Dunn, is almost completely inhibited by 8-azaguanine, no matter at which stage of growth the cells used in the experiment are harvested. Formation of glucozymase and of catalase is much less sensitive to inhibition by 8-azaguanine, and completely insensitive at certain stages of growth. Inhibition of enzyme formation by 8-azaguanine can be reversed by further addition of guanine or xanthine or hypoxanthine to the system. When inhibition of enzyme formation by 8-azaguanine is reversed by guanine there is no diminution in the amount of 8-azaguanine incorporated into RNA, but nucleic acid synthesis, as measured by incorporation of (C14)-labeled uracil, is increased. The implications of these findings in relation to involvement of RNA synthesis in enzyme formation are discussed; it is suggested that formation of different enzymes is promoted by types of RNA with different lengths of active life.