Modes of Uptake of Benzylamine by the Ehrlich Cell

Abstract

Abstract The Ehrlich ascites tumor cell shows three modes of uptake of 14C-benzylamine: an instantaneous binding, quickly reversed by washing the cell; a rapid, saturable uptake process; and a slower, apparently nonsaturable uptake process. Both the latter appear to involve predominantly if not exclusively the neutral, unprotonated form of the amine. This feature of the mediated process shows that the structure with which the amino group presumably must react is unlike the structure serving a similar role in the uptake of such amino acids as glycine, serine, and α-aminoisobutyric acid by the Ehrlich cell. Various hydrocarbon groups—branched, unbranched, and aromatic—contribute to reactivity of amines with the transport system for benzylamine, just as has been observed for the uptake of amino acids by the so-called leucine-preferring system. In this case also, the structure with which the amino group associates itself in transport is unlike those serving for amino acid transport systems in the tolerance that it shows to N-methylation of the amino group. The transport process for benzylamine appears to be similar to previously studied systems participating in the uptake of catecholamines by various tissues.