Uranic Acid Metabolism in Bacteria I. PURIFICATIOK AND PROPERTIES OF URONIC ACID ISOMERASE IN EXCHERICHIA COLI

A new metabolic pathway for the metabolism of uranic acids in bacteria has been reported briefly (l-4). According to this reaction sequence, glucuronic and galacturonic acid are isomerized to form their corresponding keto-analogues, fructuronic and tagaturonic acid,’ respectively. In the presence of reduced diphosphopyridine nucleotide, fructuronic acid is reduced to Dmannonic acid whereas tagaturonic acid yields n-altronic acid. At this point, the dual pathway converges by means of a dehydration reaction whereby 2-keto-3-deoxy-D-gluconic acid is formed. The latter compound is phosphorylated by adenosine triphosphate to yield 2-keto-3-deoxy-6-phosphogluconic acid which, in turn, is cleaved to form pyruvic acid and triose phosphate. The reaction scheme is illustrated in Fig. 1. The present paper is concerned with the purification and properties of uranic acid isomerase, and with further documentation on the identity of the reaction products.