Cytochrome b5 and Cytochrome b5 Reductase from a Chemical and X-Ray Diffraction Viewpoint
The endoplasmic reticulum of mammalian liver cells contains two major electron-transport enzyme systems. One of these is the NADH-linked cytochrome b 5 system which catalyzes the desaturation of fatty acids. The other is the NADPH-linked cytochrome P-450 system which catalyzes the hydroxylation of steroids, drugs, carcinogens, and other lipid-soluble substances. Although there is some interaction between these two systems (Lu et al., 1974), the following discussion will limit itself to the cytochrome b 5 system.
KeywordsHeme Group Phospholipid Vesicle Sulfite Oxidase Catalytic Fragment Heme Orientation
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- Diamond, R., 1971, A real-space refinement procedure for proteins, Acta Crystallogr. A27:436–452.Google Scholar
- Jacobi, T. H., Ellis, R. A., and Fritsch, J. M., 1972, Molecular modeling system, Appendix in: Polypeptide conformation of cytoplasmic malate dehydrogenase from an electron density map at 3.0 Å resolution (E. Hill, D. Tsernoglou, L. Webb, and L. J. Banaszak), J. Mol. Biol. 72:577–591.CrossRefGoogle Scholar
- Kondo, K., Tajima, S., Sato, R., and Narita, K., 1979, Primary structure of the membrane binding segment of cytochrome b 5, J. Biochem. (Tokyo) 86:1119–1128.Google Scholar
- LaMar, G. N., Burns, P. D., Jackson, J. T., Smith, K. M., and Srittmatter, P., 1981, Proton magnetic resonance determination of the relative heme orientations in disordered native and reconstituted fer-ricytochrome b 5, J. Biol. Chem. 256:6075–6079.Google Scholar
- Oshino, N., Imai, Y., and Sato, R., 1971, A function of cytochrome b 5 in fatty acid desaturation by rat liver microsomes, J. Biochem. (Tokyo) 69:155–167.Google Scholar
- Ozols, J., 1979, Proteolytic cleavage and automatic sequence analysis of cytochrome b 5 bound to lipid vesicles, Fed. Proc. 38:472.Google Scholar
- Strittmatter, P., 1961a, The nature of the flavin binding in microsomal cytochrome b 5 reductase, J. Biol. Chem. 236:2329–2335.Google Scholar
- Strittmatter, P., 1961b, The binding of pyridine nucleotides to cytochrome b 5 aporeductase, J. Biol. Chem. 236:2336–2341.Google Scholar
- Tajima, S., and Sato, R., 1980, Topological studies of the membrane-binding segment of cytochrome b 5 embedded in phosphatidyl vesicles, J. Biochem. (Tokyo) 87:123–134.Google Scholar
- Takesue, S., and Omura, T., 1970, Solubilization of NADH-cytochrome b 5 reductase from liver microsomes by lysosomal digestion, J. Biochem. (Tokyo) 67:259–266.Google Scholar
- Tanford, C., 1980, The Hydrophobic Effect, John Wiley and Sons, New York, pp. 205–211.Google Scholar
- Wyckoff, H. W., Doscher, M., Tsemoglou, D., Inagami, T., Johnson, L. N., Hardman, K. D., Allewell, N. M., Kelly, D. M., and Richards, F. M., 1967, Design of a diffractometer and flow cell system for X-ray analysis of crystalline proteins with applications to the crystal chemistry of ribonuclease-S, J. Mol. Biol. 27:563–578.PubMedCrossRefGoogle Scholar