Glucose-6-phosphate dehydrogenase and its deficiency in mutants of Corynebacterium glutamicum.
Corynebacterium glutamicum is a member of a group of taxonomically related glutamate-excreting bacteria which utilize glucose both by the Embden-Meyerhof and the pentose phosphate pathways, the latter sequence accounting for 10 to 38% of the glucose metabolized. Some of the properties of glucose-6-phosphate dehydrogenase in crude extracts of C. glutamicum were studied. The enzyme was rapidly inactivated by dilution in tris (hydroxymethyl)aminomethane-hydrochloride buffer. This inactivation was prevented by the presence of 0.45 m NaCl. Mg(++) was required for enzyme activity, but Mn(++), Ca(++), Sr(++), and Ba(++) were equally effective. Growth of the organism under differing conditions did not markedly affect the specific activity of the enzyme. A generally applicable method for detecting colonies deficient in glucose-6-phosphate dehydrogenase was developed. Mutants so obtained were found to be auxotrophic for tryptophan. Upon reversion of the tryptophan requirement, the revertants still retained the property of glucose-6-phosphate dehydrogenase deficiency. Neither the mutants nor the revertants could grow as rapidly as the parent culture in glucose, in gluconate, or in a complex medium.
D002021:Buffers; D003352:Corynebacterium / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000302:isolation & purification; D008274:Magnesium / Q000494:pharmacology; D009154:Mutation; D010734:Phosphogluconate Dehydrogenase / Q000302:isolation & purification; D012965:Sodium Chloride / Q000494:pharmacology; D014364:Tryptophan / Q000378:metabolism
D002021:Buffers; D012965:Sodium Chloride; D014364:Tryptophan; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D008274:Magnesium