A Transport System Common to Imino Acids and Glycine

An intracellular transport of proline and glycine was examined by using Ehrlich ascites carcinoma cells. The pH optima and the effect of heat inactivation on the intracellular uptake were found to be completely the same for both proline and glycine. The Michaelis type constant of glycine transport was the same as its inhibition constant to the proline transport. Moreover the Michaelis type constant of proline transport was almost the same as its inhibition constant to the glycine transport. The inhibition constants of hydroxyproline, and also of cycloleucine, were proved to be the same as those of both proline and glycine transport. From these results the existence of a transport system common to both imino acids and glycine was emphasized.