BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS THR CHEMICAL SYNTHESIS OF 2-K&TO-3-DEOXY-OCTONATR AND ITS CLEAVAGE BY A SPECIFIC ALDOLASEl

Received April 9, 1963 We have previously reported (Heath and Ghalambor, 1963) the occurrence of 2-keto-3-deoxy-octonate @DO) as a glycosidically-bound constituent of cell wall lipopolysaccharide (LPS) of Rscherichia coli 0111-B& and the enzymatic synthesis of CMP-RDO (Ghalambor and Heath, 1963). This report presents evidence for the chemical synthesis of KDO and its enzymatic cleavage (RDO-aldolase) to yield equimolar quantities of pyruvate and D-arabinose. Materials and Methods--All compounds and enzymes were obtained from commercial sources except as indicated below. The following materials were prepared as previously described (Heath and Ghalambor, 1963): D-arabinose 5phosphate; natural RDO isolated from LPS or prepared enzymatically; synthetic barium 3-deoxy-D-arabino-heptulosonate T-phosphate (Sprinson, l&C), a gift from Dr. David B. Sprinson, Columbia University, New York, was converted to its dephosphorylated derivative (RDH). N-Acetyl-neurarainate, N-acetyl-Dmannosamine, and 2-keto-3-deoxy-gluconate (KDG) were gifts from Dr. Saul Roseman of this Unit. D-Ribulose was prepared chemically from D-arabinose (Barnett and Reichstein, 1937). The following analytical methods were employed: 2-keto-3-deoxy-onic acids by the thiobarbituric acid (TBA) method of Waravdekar and Saslaw (1959)