EC Number   |
General Information |
Reference |
|---|
   7.2.1.3 | evolution |
the enzyme is a member of the CYB561 protein family |
744757 |
| 7.2.1.3 | malfunction |
mutation of His residues coordinating the intra-vesicular-side heme-b results in an almost complete loss of protein, while mutation of His residues coordinating the cytosolic-side heme-b hardly affects the expression of CYB561 proteins but results in a changed reducibility and heme content of these proteins |
744757 |
| 7.2.1.3 | malfunction |
mutation of His residues coordinating the intra-vesicular-side heme-b results in an almost complete loss of protein, while mutation of His residues coordinating the cytosolic-side heme-b hardly affects the expression of CYB561 proteins but results in a changed reducibility and heme content of these proteins. Replacing any of the 4 highly conserved His residues, coordinating the two b-type hemes, by Ala in mouse rLCytb completely abolishes the transmembrane ferric reductase activity of rLCytb |
744757 |
| 7.2.1.3 | metabolism |
enzyme is reduced by dihydrolipoic acid almost as efficiently as by ascorbate |
727395 |
| 7.2.1.3 | metabolism |
oxidized Cyt b561 is reduced by ascorbate |
728698 |
| 7.2.1.3 | more |
conserved Lys83 residue in a cytosolic loop plays a very important role for the binding of ascorbate and the succeeding electron transfer via electrostatic interactions. Lys83 might also be responsible for the intramolecular electron transfer to the intravesicular heme. Conserved residues Ser118 and Trp122, located in the putative monodehydroascorbate radical binding site, do not have major roles for the redox events on the intravesicular side |
744309 |
| 7.2.1.3 | more |
cytochrome b561 (CYB561) proteins are ascorbate reducible, transmembrane proteins consisting of 200-300 amino acids, about half of which are hydrophobic. CYB561 proteins have six transmembrane helices and two b-type hemes, one on each side of the membrane. The two heme-b centers are coordinated by two pairs of His residues localized in the central four transmembrane domains, probably very close to the membrane interface. The midpoint redox potentials of the two hemes are above 0 mV and about 100 mV apart from each other. The binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that are inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb |
744757 |
| 7.2.1.3 | more |
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that are inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview |
744757 |
| 7.2.1.3 | more |
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview |
744757 |
| 7.2.1.3 | more |
the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb |
744757 |
