<prompt> In Beri-Beri, which enzyme activity is measured?TransketolaseTranaminaseDecarboxylaseDeaminase  <response>: Severe thiamine deficiency is associated with: Decreased RBC transketolase activity this is the earliest manifestation seen even before clinical disturbances Thiamin is a cofactor of Transketolase pyruvate, alpha-ketoglutarate and lactate level in blood increases in thiamine deficiency ref: DM Vasudevan 8th ed page 467 