tokens: We studied a thiamine - dependent enzyme , transketolase , from fibroblasts of a diabetic patient who developed Wernicke's encephalopathy when treated with tolazamide , in order to delineate if this patient also had transketolase abnormality [ high Km for thiamine pyrophosphate ( TPP )], as previously reported in postalcoholic Wernicke-Korsakoff syndrome .