Labile Methyl Group Biosynthesis in the Turkey Poult

THE first evidence relating choline to methionine was the observation that methionine, as well as choline, was lipotropic for rats (Tucker and Eckstein, 1937). White and Beach (1937) demonstrated that homocystine could stimulate growth of rats fed a methionine deficient diet and postulated the conversion of homocystine to methionine, du Vigneaud et al. (1939) showed that choline was responsible for this conversion and Simmonds et al. (1943) showed that a methyl group from choline was transferred in the formation of methionine from homocystine. Bremer and Greenberg (1960) have established that all the methyl groups of choline were derived from methionine via transmethylation. It had been observed that some rats grew even though the diet was deficient in choline and methionine (du Vigneaud et al., 1939) Similar effects were shown to be due to a factor present in liver (Bennett and Toennies, 1946). The isolation of vitamin B12 (Rickes et al.,…