ERYTHROCYTE TRANSKETOLASES IN ALZHEIMERS- DISEASE

Abnormalities of thiamin metabolism have been reported in senile demen tia of Alzheimer's type (SDAT). Transketolases (TK) were studied in 21 patients with SDAT, 24 age-matched controls and 12 chronic alcoholics . Erythrocytes were assessed for their TK activity coefficient (TK-AC, normal value 8.4 +/- 12.6%) and affinity for thiamin pyrophosphate (K m TPP normal value 17.8 +/- 8.3 mumol). Comparison between study group s and controls demonstrated increased TK-AC in SDAT (16.6 +/- 15.7%, P < 0.05) and chronic alcoholism (43.4 +/- 40.6%, P < 0.05), and increa sed Km TPP (38.3 +/- 25.2 mumol, P < 0.01) in SDAT only. These finding s suggest structural abnormalities of TK rather than vitamin B1 defici ency in SDAT.