The oxidative pathway of carbohydrate metabolism in Escherichia coli. 2. Quantitative studies of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase

Abstract

Escherichia coli, strain B, growing on glucose metabolized 8.5 x 107 molecules of glucose/cell/min. Enzymes extracted from cells grown on glucose oxidized glucose 6-phosphate at a rate equivalent to 2.6-6.9 x 107 molecules/cell/min. and phosphogluconate at a rate equivalent to 2.0.3.8 x 107 molecules/ cell/min. E. coli growing on potassium gluconate metabolized 6.3 x 107 molecules of gluconate/cell/min. Enzymes extracted from cells grown on potassium gluconate oxidized glucose 6-phosphate at a rate equivalent to 2.2-5.2 x 107 molecules/cell/ min. and phosphogluconate at a rate equivalent to 1.5-2.6 x 107 molecules/cell/min. These enzymes are still present though decreased in amt. in cells which have exhausted their carbon source. Thus enzymes of the oxidative pathway were extracted from growing cells which account for approx. 40% of the total metabolism of carbohydrate.