Transamination and asymmetry in glutamate transport across the basolateral membrane of frog small intestine

Transport of L-glutamate across the basolateral membrane of frog small-intestinal epithelium, unlike that of L-alanine, is highly asymmetric; thus the rate constant (K entry) describing the entry of glutamate into the epithelium from the vascular bed across this membrane is one order of magnitude greater than the rate constant (K exit) describing its exit. This asymmetry, which appears not to depend upon the Na gradient, may be important in maintaining a high intracellular concentration of glutamate relative to alanine thereby favouring the production of alanine from glutamate by transamination.