Open AccessApparent dependence of interactions between cytochrome b5 and cytochrome b5 reductase upon translational diffusion in dimyristoyl lecithin liposomes.
Author(s) -
Philipp Strittmatter,
Michael J. Rogers
Publication year - 1975
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.72.7.2658
Subject(s) - chemistry , cytochrome b5 , liposome , vesicle , electron transfer , cytochrome , flavoprotein , phospholipid , phosphatidylcholine , bilayer , electron transport chain , cytochrome c , synthetic membrane , crystallography , membrane , photochemistry , enzyme , biochemistry , mitochondrion
Dimyristoyl lecithin liposomes, containing cytochrome b5 reductase (NADH:ferricytochrome b5 oxidoreductase, EC 1.6.2.2) and varying amounts of cytochrome b5, were used to measure flavoprotein catalysis alone and catalysis requiring electron transfer between the reductase and cytochrome as a function of temperature. Whereas flavoprotein catalysis showed a simple linear temperature dependence in an Arrhenius plot, the reaction involving electron transfer between the two bound enzymes showed a marked, 4-fold, change in rate at the crystalline-liquid crystalline phase transition of the hydrocarbon chains of the lecithin vesicles and a second, minor change involving the minor transition. These data represent strong evidence that protein-protein interactions in this membrane model system are dependent upon translational diffusion of nonpolar segments of the proteins in the hydrocarbon region of the phospholipid bilayer.