Although no studies have addressed whether alcohol directly affects TPK in humans, indirect analyses have found that the ratio of phosphorylated thiamine (primarily ThDP) to thiamine is significantly lower in alcoholics than in nonalcoholics (Poupon et al.
As mentioned earlier, once thiamine is imported into the cells, it is first converted into ThDP by the addition of two phosphate groups.
These investigators found that transketolase from the Korsakoff's patients bound ThDP less avidly than did the enzyme from the control subjects.
This analysis found that the enzyme from the alcoholic men and their sons also bound ThDP less strongly than did the enzyme from the healthy volunteers and their sons (fathers and sons were similar to each other in both groups).
Other investigators, however, have found no differences in the ability of transketolase from Korsakoff's patients and healthy subjects to bind ThDP (Nixon et al.