The plant plasma membrane b-type cytochrome : a review
Faculty of Sciences. Biology
Belgian journal of botany / Royal Botanical Society of Belgium. - Brussels, 1990 - 2009
Bulletin de la Société royale de botanique. - Bruxelles, 1862 - 1989
, p. 171-183
University of Antwerp
The plasma membrane of higher plants contains a specific b-type cytochrome. This major component has a high standard redox potential (average E'(0) of + 140 mV) and an a-band absorption maximum near 561 nm. Ascorbic acid rapidly reduces the cytochrome but NADH or NADPH are ineffective as a reductant. The redox protein has been detected in purified plasma membranes of a variety of plant species and tissues and it appears to be a common plasma membrane component. Specific concentrations range from 20 to 400 pmol per mg protein. Initial attempts to purify the protein indicated a molecular weight of 31 kDa and suggest that the cytochrome may be a glycoprotein. The current hypotheses on the physiological importance of the plant plasma membrane cytochrome are focused on ascorbate-mediated transmembrane electron transport and blue light photoperception.