METABOLISM OF FRUCTOSE-1,6-DIPHOSPHATE AND ACETATE IN ACETOBACTER SUBOXYDANS

Abstract

Fructose-1,6-diphosphate is converted to 3-phosphoglyceric acid by cell-free extracts of A. suboxydans 621. The participation of triosephosphate dehydrogenase could be demonstrated only when the pentose cycle was blocked either through the removal of Mg++ by dialysis against a suspension of Dowex-50 or by complexing with ethylenediaminetetraacetic acid. Under these circumstances a DPN-specific oxidation of fructose-1,6-diphosphate could be demonstrated. The responsible dehydrogenase exhibited characteristic sulfhydryl properties. Subsequent metabolism of 3-phosphoglyceric acid appeared to be oxidative but no product was identified. The same enzyme preparation converts acetate or pyruvate to acetyl-CoA when the appropriate cofactors are present. However, citrate formation or acetylation of arylamines does not occur without the introduction of a foreign acceptor enzyme. Carboxyl-C14-labeled acetate becomes incorporated into cellular constituents, particularly lipids, in the presence of an added source of energy. The C14 does not appear in the respiratory gases.