Lysine uptake by rat renal brush-border membrane vesicles.

Lysine uptake by isolated rat renal brush-border membrane vesicles occurs via a single saturable system plus a significant diffusion component with indication of a single energy of activation on an Arrhenius plot. Initial uptake is not sodium dependent, and intravesicular accumulation of lysine at longer time points is greatest in the absence of sodium. Accumulation levels differ in the presence or absence of NaCl or choline chloride and are specific for the cation used. Lysine uptake is membrane potential sensitive and inhibitable by cystine, dibasic amino acids, and cycloleucine. Heteroexchange diffusion of lysine with cystine and lysine with arginine occurs, but no heteroexchange occurs with cycloleucine, indicating that lysine shares a transport system with cystine and dibasic amino acids but not with cycloleucine.