Kinetics of Naplus-dependent amino acid transport using cells and membrane vesicles of a marine pseudomonad

Abstract

Sodium ion is required for transport of L-alanine and alpha-aminoisobutyric acid (AIB) into cells and membrane vesicles of a marine pseudomonad. Initial rate data obtained at various Naplus and amino acid concentrations were tested for fit by least squares analysis to sequential and Ping-Pong equations. The sequential case is preferred statistically at the 99% confidence limit. Cotransport of AIB and Naplus in cells could not be detected, perhaps explained by efflux of Naplus shown to occur from these cells. The kinetic analysis is consistent with formation of a ternary complex involving Naplus and the amino acid.