THE ENZYMATIC SYNTHESIS OF CITRIC ACID BY CELL-FREE EXTRACTS OFASPERGILLUS NIGER

Abstract

Cell-free extracts of Aspergillus niger, N.R.C. 233, have been shown to contain the enzymes necessary to catalyze the synthesis of citrate from ATP, acetate, and oxalacetate. The "condensing enzyme", which catalyzes the condensation of acetyl-coenzyme A and oxalacetate to yield citrate, has been isolated and purified approximately 50-fold by a combination of steps involving ammonium sulphate fractionation and calcium phosphate gel adsorption.