Abstract:Glutathione(GSH)-loaded positive plasma membrane vesicles obtained by phase partitioning of microsomal fractions from soybean ( Glycine max L. ) hypocotyls were capable of transferring electrons from internal GSH to an externally added electron receptor, such as ferricyanide (FeCN) and cytochrome (Cyt) C. The rate of reduction for FeCN and Cyt C was (21.6 ± 0.6) nmol FeCN·min- 1·mg- 1 protein and (6.6 ± 1.0) nmol Cyt C· min- 1. mg- 1 protein, respectively. The transplasma membrane electron transport was able to change the distinct absorption spectra (soret band) of Cyt P-450,which was widely present in the plant plasma membrane. This indicated that Cyt P-450 participated in the redox reaction. The transplasma membrane electron transport was associated with proton transport and the change of membrane potential.