title: Cytochrome b5, its functions, structure and membrane topology.
abstract: The first part of the present communication reviews recent advances in our understanding of the known physiological functions of cytochrome b5. In addition, one section is devoted to a description of a recently discovered function of cytochrome b5, namely its involvement in the synthesis of the oncofetal antigen N-glycolylneuraminic acid. The second part of the article summarizes site-directed mutagenesis studies, primarily conducted in the author's laboratory, in both the catalytic heme-binding and membrane-binding domain of cytochrome b5. These studies have shown that: 1) the membrane binding domain of cytochrome b5 spans the bilayer; 2) cytochrome b5 lacking 19 COOH-terminal amino acids does not bind to membrane bilayers; and 3) specific amino acids in the membrane binding domain have been mutated and shown not to be essential for the function of cytochrome b5 with its redox partners.
authors.affiliation: Department of Biophysical Chemistry, University of Basel, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Vergéres
authors.forename: L
authors.initials: L
authors.lastname: Waskell
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015786:Cytochromes b5 / Q000737:chemistry / Q000502:physiology*; D006801:Humans; D008055:Lipids / Q000096:biosynthesis*; D008565:Membrane Proteins / Q000737:chemistry / Q000502:physiology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D008055:Lipids; D008565:Membrane Proteins; D015786:Cytochromes b5