Transketolase (D-sedoheptulose-7-phosphate, D-glyceraldehyde-3-phosphate glycolaldehyde transferase E. C. 2. 2. 1. 1) has been purified from brewer's yeast according to the method of P. Srere et al. and the resolution for thiamine pyrophosphate and divalent cations has been efficiently carried out using 0.025_M glycylglycine buffer (pH7.6). Coenzyme reconstitution for the enzyme was promoted by incubating at 30℃. Thiamine pyrophosphate alone, without added divalent cation, could activate apoenzyme and was irresistibly bound to reconstitute holoenzyme. 2'-nor-Thiamine and 2'-ethylthiamine pyrophosphate showed negligible and 8%activities as the coenzymes respectively.