The incorporation experiments with labeled serine in the crude microsomal protein fraction of normal and thiamine deficient rat liver were carried out. The liver microsomal fraction of animals kept on the thiamine deficient diet showed less incorporation of lebeled serine than the normal animals.The injection of thiamine in the thiamine deficient animals two hours before killing increased to an appreciable extent the incor poration of labeled serine in microsomal protein, indicating a possible role of thiamine in protein biosynthesis. Mulgaonkerr and Sreenivasan (6) observed that in a deficiency of vitamin B12 and folic acid in rats there is a significant reduction in total serum proteins.Raskin and Kirzhner (7) reported that patients receiving vitamin Bs and B12 showed more rapid return to normal in serum protein than the patients not receiving vitamin B6 and B12. These studies indicate clearly that besides vitamin B12 there are other vitamins of B groups which may influence protein synthesis.Since much work has not been carried out on the effect of thiamine on microsomal incorporation of labeled amino acid, it has been thought worth-while to investigate whether thiamine has any in fluence on the microsomal biosynthesis of protein.
EXPERIMENTALSixty male albino rats weighing between 40 to 50g were selected for this experiment.The animals were divided into two groups o£ thirty each. The animals of group I were fed a normal diet and the animals of group II were given thiamine deficient diet. The composition of the diet for group I and group II is shown in Table 1. The pair-feeding techniques were followed in feeding the animals. The animals were weighed weekly. The normal and thiamine deficient animals were killed periodically by decapitation. The thiamine content of different tissues was estimated by the method of Harris and Wong (8). The blood pyruvic acid was estimated according to the method of Klein (9). The results are shown in Tables 2 and 3.