Evidence for Active Transport of the Dipeptide Glycylsarcosine by Hamster Jejunum in Vitro

1. Glycylsarcosine, a peptide which is slowly hydrolysed by the intestine, is transported into the jejunal mucosal cells of the hamster by an active Na + -dependent process. 2. Uptake of glycylsarcosine is inhibited by l-methionyl-l-methionine but not by l-methionine, suggesting that l-methionyl-l-methionine and glycylsarcosine share an uptake mechanism which is independent of that for free methionine, and that l-methionyl-l-methionine may also enter the cells.