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Effect of papain digestion on redox‐linked proton translocation in b ‐ c 1 complex from beef heart reconstituted into liposomes
Author(s) -
Lorusso M.,
Gatti D.,
Marzo M.,
Papa S.
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80335-5
Subject(s) - chemistry , protein subunit , papain , chromosomal translocation , proteolysis , liposome , proton , biophysics , biochemistry , enzyme , biology , physics , quantum mechanics , gene
Papain treatment of the cytochrome b ‐ c 1 complex from beef heart results in partial proteolysis of core protein II, the iron‐sulphur protein and the 15‐kDa subunit. Under these conditions a significant inhibition of electron flow and complete suppression of proton translocation in the complex reconstituted into liposomes are observed. Kinetic experiments indicate a correlation between the digestion of core protein II and 15‐kDa subunit and the suppression of proton translocation. The results suggest an active involvement of polypeptides of the complex in stabilizing the semiquinone species and/or providing pathways to exchange protons between bound quinone systems and aqueous phases.