[Cytochromes b in submitochondrial particles from beef heart in the presence of redox succinate/fumarate buffer].
Aerobic red-ox titration of cytochromes b from submitochondrial particles (SMP) using red-ox succinate/fumarate couple revealed two components, one of them having E'0=80 mv; n=1 and alpha-band absorption maximum at 562 nm (b562); and the other-E'0=-25 mv; n=1 and the absorption maximum at 565 nm. Energisation of SMP, equilibrated with red-ox succinate/fumarate buffer, brought about a increase in absorption at the cytochromes b region (564-565 nm), which was reversed and prevented by an uncoupler. Energy-dependent reverse electrone transport from ascorbate+TMPD resulted in considerable higher reduction of cytochromes b with summary maximum at 563 nm with the same initial reduction level prior to energisation. The data obtained show that energy dependent  reduction of cytochromes b of SMP poised with succinate/fumarate red-ox buffer is presumably to the effect of energisation on the red-ox state of cytochrome b566. It is suggested that the transmembrane electric potential difference, generated upon the energisation of the particles, should result in re-distribution of the semi-quinone Q anion (-Q-) across membrane, thus altering the equilibrium redox-state of respiratory carriers, interacting with redox-couples -Q/Q and QH2/-Q- in the mitochondrial membrane.
D000818:Animals; D002021:Buffers; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D003580:Cytochromes / Q000378:metabolism*; D004735:Energy Transfer; D005650:Fumarates; D008931:Mitochondria, Muscle / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D010084:Oxidation-Reduction; D013057:Spectrum Analysis; D013386:Succinates
D002021:Buffers; D003580:Cytochromes; D005650:Fumarates; D013386:Succinates
Issledovanie tsitokhromov b v submitokhondrial'nykh chastitsakh serdtsa byka v prisutstvii okislitel'no-vosstanovitel'nogo bufera suktinat/fumarat