Diffusion, active transport and metabolism of purines in the yeast Torulopsis candida.

摘要: Abstract Torulopsis candida actively accumulated guanine, xanthine and uric acid from the medium when these compounds were present as sole nitrogen sources. The yeast was able to use endogenous reserves an energy source for transport. Adenine, hypoxanthine several other purines not accumulated. Guanine, catabolized; guanase uricase but no oxidase or dehydrogenase activities detected in extracts homogenates of yeast. Although a transport system 8-azaguanine found, slowly converted 8-azaxanthine. In experiments designed study kinetics purine diffusion T. candida, hypoxanthine, 6-mercaptopurine, and, with cyanide-treated yeast, behaved expected membrane diffusion. Guanine adsorbed by adenine both normal