THE ADAPTIVE FORMATION OF UREASE BY WASHED SUSPENSIONS OF PSEUDOMONAS AERUGINOSA

Abstract

Urease is formed adaptively by suspensions of washed cells during oxidation of glucose, pyruvate, acetate or one of the Krebs cycle intermediates. When urea and oxidizable substrate are added together, there is a short latent period which is absent if urea is added after oxidation has ceased. Formation of enzyme in the absence of added urea may be due to production of small amounts of urea from endogenous purines. Added uric acid is oxidized to equivalent amounts of urea. Uric acid added after a period of oxidation yields equivalent amounts of NH3 since urease is formed already. O2 consumption and CO2 evolution suggest oxidation of uric acid via allantoin, allantoic acid, and glyoxylic acid. Urease formation is inhibited by (NH4)2SO4, the N of which is assimilated during oxidation. N assimilation and urease formation may compete for energy made available by oxidation. Urea present during the period of oxidation also inhibits enzyme formation probably by forming NH3 which is assimilated.