Transport and exchange diffusion of l-tryptophan in Ehrlich cells

Abstract

The initial velocity of uptake of l-tryptophan by Ehrlich ascites cells can be explained as the sum of two processes: diffusion and an active transport that shows a saturation effect. Azaserine, l-2,4 diaminobutyric acid, l-histidine, and l-leucine, at low concentrations, increase the initial velocity of uptake of l-tryptophan but compete with l-tryptophan at high concentrations. Preliminary loading of the cells with glycine decreases the initial tryptophan flux: preliminary loading of the ascites cells with azaserine or tryptophan markedly increases the initial flux of uptake of the other amino acid.