The soluble fraction of the homogenates of the liver, kidneys, small intestines, heart, lungs, spleen and brain in the rat was obtained by Spinco ultracentrifuge (100,000×g, 60min.), and the phosphorylating activity of thiamine in the supernatant was studied. The reaction mixture contained thiamine (5μg), ATP (10^<-3>M) as a phosphate donor, Mg^<2+>(10^<-3>M) and the fraction. The activity was found in the liver, kidneys and intestines but not in the spleen, heart, lungs and brain.
