REACTIONS OF ENOLIC SUGAR DERIVATIVES .5. STUDIES ON CONVERSION OF THYMIDINE DIPHOSPHATE D-GLUCOSE TO THYMIDINE DIPHOSPHATE 4-KETO-6-DEOXY-D-GLUCOSE USING THYMIDINE DIPHOSPHATE D-[U-14C 5-3H) GLUCOSE

Chemically synthesized TDP‐d‐[U‐14C,5‐3H]glucose was converted to TDP‐4‐keto‐6‐deoxy‐d‐[U‐14C,6‐3H]glucose by an enzyme system system obtained from Escherichia coli B. The product contained only a minor amount of the tritium originally present in the starting material. Elimination of tritium from the starting material paralleled the formation of the keto‐product. This result is interpreted as indicating that a 5,6‐unsaturated hexose nucleotide is an intermediate in the overall conversion. Part of the tritium eliminated from the 5‐position of d‐glucose was reincorporated into the 6‐position of the end product. The mechanistic implications of these results are discussed. Copyright © 1968, Wiley Blackwell. All rights reserved