Identification of thiamine diphosphate-binding proteins from rat liver supernatant.

Transketolase (EC 2.2.1.1) was shown to be the sole enzyme protein bound to thiamine diphosphate (ThDP) as coenzyme in the soluble fraction of rat liver. No new ThDP-binding proteins with the molar ratio of ThDP to protein of 1.0 were detected in the rat liver supernatant under the purification and assay conditions employed.