Effect of 8-Azaguanine on Enzyme Formation

Abstract

THE dependence of enzyme formation on nucleic acids has now been established by studies with disrupted Staphylococci ¹. It is not yet clear whether the presence of ribonucleic acid as such or the process of synthesis of ribonucleic acid is essential for enzyme synthesis. Gale and Folkes¹ found that the development of certain enzyme systems was enhanced by the presence of ribonucleic acid extracted from the cells, whereas such extracts were without effect in promoting the synthesis of β-galactosidase, which required the presence of a mixture of purines and pyrimidines and was abolished by ribonuclease. Pardee², studying the formation of β-galactosidase in mutants of ^{Escherichia coli} requiring uracil, found that enzyme formation only took place in the presence of added uracil and, if the supply of uracil was limiting, enzyme synthesis ceased as soon as the supply of uracil was exhausted. He concluded that ribonucleic acid synthesis was essential for enzyme formation, the finished nucleic acid being metabolically inert. Similar conclusions have been drawn by Spiegelman, Halvorson and Ben-Ishai³ as a result of investigations on inducible enzyme synthesis in Escherichia coli and in yeasts.