Study of spin-labeled microsomal membrane proteins by their reaction with ascorbic acid
Kocherginskiĭ, N.M.; S"iakste, N.I.; Berkovich, M.A.; Biniukov, V.I.; Devichenskiĭ, V.M.
Biofizika 26(2): 306-311
1981
ISSN/ISBN: 0006-3029 PMID: 6266508 Document Number: 168822
Kinetics of the reduction of nitroxyl radicals bound to SH-groups of rat microsomal membrane proteins by ascorbic acid was investigated. The reduction involves 2 steps. During the 1st rapid step mainly the radicals with weak immobilization located on the membrane surface are reduced. At the 2nd slow step more immobilized radicals located in hydrophobic membrane regions take part in the reaction. A kinetic analysis of the process showed that the slow step is not determined by the slow movement of proteins of their fragments, e.g., from the membrane depth to its surface, and apparently is conditioned by lower ascorbic acid concentration in the membranes.