A kinetic model for the effects of vanadate on human erythrocyte membrane

摘要

The effects of vanadate on human erythrocyte membrane have been investigated with stopped-flow and equilibrium fluorescence quenching techniques. The equilibrium study showed a half-quenching concentration (K1/2) of 0.27 mmol·L-1. The stopped-flow experiment exhibited a fast rise (t1、2f～1s) and a slow drop (t1/2s 1～2 min) in fluorescence. Based on the results and that from the across membrane transport of vanadate, a kinetic model is proposed which suggests that the membrane proteins experience a series of conformational changes before and during the quenching of the intrinsic fluorescence. These changes are induced mainly by three kinds of interactions: （i） the long-distance, non-specific interaction between the vanadate and the erythrocyte membrane surface, （ⅱ） the charge interaction between the vanadate and parts of the membrane proteins, and（ⅲ） the binding of the vanadate to some membrane proteins.