Incorporation of Integral Membrane Proteins into Liposomes
One of the most intriguing features of biological membranes is their asymmetry. A variety of techniques has shown that most membrane components are not randomly distributed, but specifically oriented with respect to the two membrane surfaces (1,2). In the case of the mitochondrial inner membrane, cytochromes c and cl are localized on the outer side (C-side) and the mitochondrial ATPase F1 on the inner or matrix side (M-side) of the membrane (2). Cytochrome c oxidase spans the membrane (3–5) so that some subunits of this oligomeric enzyme are situated on the outer side, some on the inner side and some in the interior of the membrane (4). We are beginning to understand how this asymmetric architecture determines the various vectorial functions of biological membranes but we know next to nothing about how this asymmetry arises in vivo. For example, it would be interesting to know to what extent the asymmetric transmembranous orientation of cytochrome oxidase is caused by an asymmetry in the enzyme itself, or by specific properties such as charge, curvature, phospholipid asymmetry or protein composition of the receptor membrane.
KeywordsCytochrome Oxidase Respiratory Control Protein Ratio Hydrophobic Protein Respiratory Control Ratio
respiratory control ratio
mitochondrial ATPase (oligomycin-insensitive)
hydrophobic protein fraction from mitochondria required for formation of the proton channel of the transmembranous ATPase complex
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- 2.Racker, E. (1970) in Essays in Biochemistry (P.N. Campbell and F. Dickens, eds.) Academic Press. Vol, 6, P. 1–22.Google Scholar
- 5.Hackenbrock, C.R. and Hammon, K.M. (1975) J. Biol. Chem. 250, 9185–9197.Google Scholar
- 6.Kagawa, Y. and Racker, E. (1971) J. Biol. Chem. 246, 5477–5487.Google Scholar
- 15.Racker, E. (1975) in Proceedings of the Tenth FEBS Meeting (J. Montreuil and P. Mandel, eds.) North-Holland/American Elsevier, Vol. 41, pp. 25–34.Google Scholar
- 17.Racker, E., Chien, T-F. and Kandrach, A. (1975) FEBS Letters, 57, 14–1 8.Google Scholar
- 18.Miller, C. and Racker, E. (1976), J. Membrane Biology, in press.Google Scholar
- 26.Slonimski, P.P. (1953) La formation des enzymes respiratoires chez la levure, Masson, Paris.Google Scholar