Enzymic preparation of specifically 14C and 3H labelled shikimic acids

Abstract D‐Shikimic acids 1− 14 C, 6− 14 C and 7‐(carboxyl) 14 C have been biosynthetically prepared with specific activities of about 25 mCi/mmole and with overall yields of 45% based on pyruvate 3,2 or 1− 14 C as the respective starting materials. A crude cellfree homogenate of E. coli 83–24 was used to catalyze the condensation of phosphoenolpyruvate− 14 C with unlabelled erythrose‐4‐phosphate to give shikimic acid. Phosphoenolpyruvate− 14 C was synthesized from pyruvate− 14 C and ATP by the action of phosphoenolpyruvate‐synthase. Erythrose‐4‐phosphate 1,2,3,4− 14 C and erythrose‐4‐phosphate‐4‐T was prepared from glucose‐U− 14 C and glucose‐6‐T via enzymatic phosphorylation to labelled glucose‐6‐phosphate and subsequent lead tetraacetate oxidation. Condensation of labelled E‐4‐P with unlabelled PEP gave rise to shikimic acid‐2,3,4,5− 14 C and 2‐T.