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Literature summary for 7.2.1.3 extracted from

  • Berczi, A.; Zimanyi, L.
    The trans-membrane cytochrome b561 proteins structural information and biological function (2014), Curr. Protein Pept. Sci., 15, 745-760 .
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
cloning and recombinant expression of untagged four CYB561 isoforms in yeast YPH499 cells, recombinant expression of two C-terminally His10- or Strep-II-tagged CYB561 paralogues in either Escherichia coli or in Pichia pastoris. Functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 deficient in ferric reductase activity Arabidopsis thaliana
functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 deficient in ferric reductase activity Zea mays
functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 which is deficient in ferric reductase activity Schistosoma japonicum
recombinant expression of C-terminally His6-tagged isozyme CGCytb in Spodoptera frugiperda Sf9 cells as well as in Pichia pastoris strain GS115, and recombinant expression of C-terminally His6-tagged isozyme CGCytb in Escherichia coli Bos taurus
recombinant expression of C-terminally His6-tagged isozyme DCytb in Spodoptera frugiperda Sf9 cells, untagged, apoform or fully functional isozyme DCytb in Escherichia coli Homo sapiens
recombinant expression of C-terminaly His6-tagged enzyme in yeast YPH499 cells, recombinant expression of C-terminally His6-tagged isozyme DCytb in Escherichia coli Mus musculus

Protein Variants

Protein Variants Comment Organism
E79A site-directed mutagenesis, the mutation in bovine rCGCytb causes significant (but no extreme) alteration in at least one of the two (sometimes three) midpoint ascorbate concentrations characterizing the redox transition of hemes-b, and the mutation does not block the reduction of either heme-b center Bos taurus
H108A site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility Mus musculus
H117A site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb Arabidopsis thaliana
H120A site-directed mutagenesis of DCytb, the mutation results in partial loss of hemes Homo sapiens
H120A site-directed mutagenesis, the mutation results in nearly undetectable levels of rCGCytb Mus musculus
H156A site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb Arabidopsis thaliana
H159A site-directed mutagenesis of DCytb, the mutation results in partial loss of hemes Homo sapiens
H159A site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility Mus musculus
H33A site-directed mutagenesis, mutation in human DCytb does not influence the physicochemical properties of protein as compared to the wild-type Homo sapiens
H50A site-directed mutagenesis of DCytb, the mutation results in complete loss of hemes Homo sapiens
H50A site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb Arabidopsis thaliana
H50A/H120A site-directed mutagenesis of DCytb, the mutant contains one heme-b per double His-mutant rDCytb Homo sapiens
H52A site-directed mutagenesis, the mutation results in nearly undetectable levels of rCGCytb Mus musculus
H83A site-directed mutagenesis, no alteration is found from the ascorbate reducibility compared to mouse wild-type rCGCytb Mus musculus
H83A site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb Arabidopsis thaliana
H83A/H156A site-directed mutagenesis Arabidopsis thaliana
H83L/H156L site-directed mutagenesis Arabidopsis thaliana
H86A site-directed mutagenesis of DCytb, the mutation results in complete loss of hemes Homo sapiens
H86A site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility Mus musculus
H86A/H159A site-directed mutagenesis of DCytb, the mutant contains one heme-b per double His-mutant rDCytb Homo sapiens
H86A/H159A site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility Mus musculus
K81A/R150A/F105W/H106E site-directed mutagenesis, the quadruple mutation completely prevents ascorbate from reducing the protein, inactive mutant Arabidopsis thaliana
K83A site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type Zea mays
K83D site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type Zea mays
K83E site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type Zea mays
additional information 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. Midpoint ascorbate concentration for the reduction of low-potential heme-b centers is hardly influenced by the R74X replacements but that for the high-potential heme-b centers show a significant trend Mus musculus
N78K site-directed mutagenesis, the mutation in bovine rCGCytb does not influence the physicochemical properties of protein as compared to the wild-type Bos taurus
R72A site-directed mutagenesis, the mutant shows reduced activity compared to wild-type Mus musculus
R72E site-directed mutagenesis, the mutant shows reduced activity compared to wild-type Mus musculus
R72E site-directed mutagenesis, the mutation of TCytb does not affect the final reduction level of rTCytb by ascorbate but results in a complete loss of the pH-dependent initial time-lag upon electron acceptance from ascorbate Mus musculus
R72K site-directed mutagenesis, the mutant shows reduced activity compared to wild-type Mus musculus
R72T site-directed mutagenesis, the mutant shows reduced activity compared to wild-type Mus musculus
R72Y site-directed mutagenesis, the mutant shows reduced activity compared to wild-type Mus musculus
S118A site-directed mutagenesis, mutation in maize TCytb does not influence the physicochemical properties of protein as compared to the wild-type Zea mays
T84A site-directed mutagenesis, the mutation in bovine rCGCytb causes significant (but no extreme) alteration in at least one of the two (sometimes three) midpoint ascorbate concentrations characterizing the redox transition of hemes-b, and the mutation does not block the reduction of either heme-b center Bos taurus
W122A site-directed mutagenesis, mutation in maize TCytb does not influence the physicochemical properties of protein as compared to the wild-type Zea mays

Localization

Localization Comment Organism GeneOntology No. Textmining
brush border of duodenal mucosa Mus musculus 5903
-
chromaffin granule membrane CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins Bos taurus 42584
-
chromaffin granule membrane CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins Mus musculus 42584
-
chromaffin granule membrane CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins Homo sapiens 42584
-
lysosome LCytb Bos taurus 5764
-
lysosome LCytb Mus musculus 5764
-
lysosome LCytb Homo sapiens 5764
-
membrane a transmembrane enzyme, CYB561 proteins have six trans-membrane helices and two b-type hemes, one on each side of the membrane Schistosoma japonicum 16020
-
membrane a transmembrane enzyme, in the vacuolar (tonoplast) membrane. CYB561 proteins have six trans-membrane helices and two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling Arabidopsis thaliana 16020
-
membrane a transmembrane enzyme, in the vacuolar (tonoplast) membrane. CYB561 proteins have six transmembrane helices and two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling Zea mays 16020
-
membrane a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a trans-membrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling Bos taurus 16020
-
membrane a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a transmembrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling Mus musculus 16020
-
membrane a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a transmembrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling Homo sapiens 16020
-
microsome
-
Bos taurus
-
-
tonoplast TCytb Arabidopsis thaliana
-
-
tonoplast TCytb Zea mays
-
-
vacuolar membrane TCytb Arabidopsis thaliana 5774
-
vacuolar membrane TCytb Zea mays 5774
-

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
ascorbate[side 1] + Fe(III)[side 2] Arabidopsis thaliana
-
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2] Bos taurus
-
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2] Mus musculus
-
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2] Zea mays
-
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2] Homo sapiens
-
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2] Schistosoma japonicum
-
monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
additional information Schistosoma japonicum a few members of the CYB561 protein family function as ferric reductases in vivo ?
-
?
additional information Bos taurus trans-membrane ferric reductase activity is also demonstrated in a reconstituted proteoliposome system with ascorbate as the electron donor inside the liposomes, recombinant CGCytb as trans-membrane electron carrier, and ferricyanide as the electron acceptor outside the liposomes. A few members of the CYB561 protein family function as ferric reductases in vivo. The other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb ?
-
?

Organism

Organism UniProt Comment Textmining
Arabidopsis thaliana Q9SWS1 four CYB561 isoforms
-
Bos taurus P10897
-
-
Homo sapiens P49447
-
-
Mus musculus Q6P1H1 LCytb
-
Schistosoma japonicum Q5D8X4
-
-
Zea mays Q6I681
-
-

Posttranslational Modification

Posttranslational Modification Comment Organism
acetylation the N-terminus of isozyme CBCytB is anchored to the membrane by acetylation of the amino-terminal Met residue Bos taurus

Purification (Commentary)

Purification (Comment) Organism
native chromaffin granule CYB561 from adrenal gland from the chromaffin granule membrane by Triton X-100 solubilzation and separation of the solubilized nCGCytb by preparative electrophoresis. Recombinant C-terminaly His6-tagged isozyme CGCytb from Spodoptera frugiperda Sf9 cells, Pichia pastoris strain GS115, or Escherichia coli by nickel affinity chromatography to homogeneity Bos taurus
recombinant C-terminally His6-tagged isozyme DCytb from Spodoptera frugiperda Sf9 cells, and untagged, apoform or fully functional isozyme DCytb from Escherichia coli, to homogeneity Homo sapiens
recombinant C-terminaly His6-tagged enzyme from yeast YPH499 cells by nickel affinity chromatography, recombinant C-terminally His6-tagged isozyme DCytb from Escherichia coli Mus musculus
recombinant untagged four CYB561 isoforms from yeast YPH499 cells partially, two recombinant C-terminally His10- or Strep-II-tagged CYB561 paralogues from Escherichia coli and Pichia pastoris by affinity chromatography Arabidopsis thaliana

Reaction

Reaction Comment Organism Reaction ID
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] reaction mechanism Arabidopsis thaliana
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] reaction mechanism Bos taurus
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] reaction mechanism Mus musculus
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] reaction mechanism Zea mays
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] reaction mechanism Homo sapiens
ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] reaction mechanism Schistosoma japonicum

Source Tissue

Source Tissue Comment Organism Textmining
adrenal gland
-
Bos taurus
-
adrenal gland
-
Mus musculus
-
adrenal gland
-
Homo sapiens
-
duodenal mucosa brush-border membrane, DCytb Mus musculus
-
macrophage
-
Bos taurus
-
macrophage
-
Mus musculus
-
macrophage
-
Homo sapiens
-
additional information the parasitic trematode Schistosoma japonicum contains a CYB561 protein localized to the schistosome tegument Schistosoma japonicum
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ascorbate[side 1] + Fe(III)[side 2]
-
Arabidopsis thaliana monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2]
-
Bos taurus monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2]
-
Mus musculus monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2]
-
Zea mays monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2]
-
Homo sapiens monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
ascorbate[side 1] + Fe(III)[side 2]
-
Schistosoma japonicum monodehydroascorbate[side 1] + Fe(II)[side 2]
-
?
additional information structure-function relationship, overview Arabidopsis thaliana ?
-
?
additional information structure-function relationship, overview Zea mays ?
-
?
additional information structure-function relationship, overview Schistosoma japonicum ?
-
?
additional information a few members of the CYB561 protein family function as ferric reductases in vivo Schistosoma japonicum ?
-
?
additional information trans-membrane ferric reductase activity is also demonstrated in a reconstituted proteoliposome system with ascorbate as the electron donor inside the liposomes, recombinant CGCytb as trans-membrane electron carrier, and ferricyanide as the electron acceptor outside the liposomes. A few members of the CYB561 protein family function as ferric reductases in vivo. The other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb Bos taurus ?
-
?
additional information enzyme assays also with purified chromaffin granule membrane ghosts, or purified proteins in detergent micelles, or in reconstituted membrane vesicles. Structure-function relationship, overview Bos taurus ?
-
?
additional information the other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb. Structure-function relationship, overview Mus musculus ?
-
?
additional information the other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb. Structure-function relationship, overview Homo sapiens ?
-
?

Subunits

Subunits Comment Organism
More Cytb561 enzyme structure analysis, structure-function relationship, detailed overview Arabidopsis thaliana
More Cytb561 enzyme structure analysis, structure-function relationship, detailed overview Bos taurus
More Cytb561 enzyme structure analysis, structure-function relationship, detailed overview Mus musculus
More Cytb561 enzyme structure analysis, structure-function relationship, detailed overview Zea mays
More Cytb561 enzyme structure analysis, structure-function relationship, detailed overview Homo sapiens
More Cytb561 enzyme structure analysis, structure-function relationship, detailed overview Schistosoma japonicum

Synonyms

Synonyms Comment Organism
CGCytb
-
Bos taurus
CGCytb
-
Mus musculus
CGCytb
-
Homo sapiens
chromaffin granule CYB561
-
Bos taurus
chromaffin granule CYB561
-
Mus musculus
chromaffin granule CYB561
-
Homo sapiens
chromomembrin B
-
Bos taurus
CYB561
-
Arabidopsis thaliana
CYB561
-
Bos taurus
CYB561
-
Mus musculus
CYB561
-
Zea mays
CYB561
-
Homo sapiens
CYB561
-
Schistosoma japonicum
cytochrome b-559
-
Bos taurus
cytochrome b561
-
Bos taurus
DCytb
-
Mus musculus
DCytb
-
Homo sapiens
ferric chelate reductase
-
Schistosoma japonicum
LCytb
-
Bos taurus
LCytb
-
Mus musculus
LCytb
-
Homo sapiens
TCytb
-
Arabidopsis thaliana
TCytb
-
Zea mays
trans-membrane ferric-chelate reductase
-
Mus musculus

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
additional information
-
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics Arabidopsis thaliana
additional information
-
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics Bos taurus
additional information
-
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics Mus musculus
additional information
-
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics Zea mays
additional information
-
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics Homo sapiens
additional information
-
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics Schistosoma japonicum

Cofactor

Cofactor Comment Organism Structure
ascorbate cytosolic ascorbate is the cellular electron donor for the CYB561 proteins Arabidopsis thaliana
ascorbate cytosolic ascorbate is the cellular electron donor for the CYB561 proteins Bos taurus
ascorbate cytosolic ascorbate is the cellular electron donor for the CYB561 proteins Mus musculus
ascorbate cytosolic ascorbate is the cellular electron donor for the CYB561 proteins Zea mays
ascorbate cytosolic ascorbate is the cellular electron donor for the CYB561 proteins Homo sapiens
ascorbate cytosolic ascorbate is the cellular electron donor for the CYB561 proteins Schistosoma japonicum
cytochrome b561 a CYB561 protein Arabidopsis thaliana
cytochrome b561 a CYB561 protein Mus musculus
cytochrome b561 a CYB561 protein Zea mays
cytochrome b561 a CYB561 protein Homo sapiens
cytochrome b561 a CYB561 protein Schistosoma japonicum
heme b two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials of heme b, comparisons Schistosoma japonicum
heme b two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons Mus musculus
heme b two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons Zea mays
heme b two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons Homo sapiens
heme b two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons. The high-potential heme-b, characterized with a low-spin EPR signal in the vicinity of gz = 3.1, is located on the cytosolic side of the protein Arabidopsis thaliana
heme b 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. CYB561 protein structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons. The high-potential heme-b center of CGCytb is located on the cytosolic side of the protein, mutational analysis Bos taurus
additional information neither ferrocyanide nor durohydroquinone can reduce nCGCytb Bos taurus
additional information neither ferrocyanide nor durohydroquinone can reduce nCGCytb Mus musculus

General Information

General Information Comment Organism
evolution the enzyme is a member of the CYB561 protein family Arabidopsis thaliana
evolution the enzyme is a member of the CYB561 protein family Bos taurus
evolution the enzyme is a member of the CYB561 protein family Mus musculus
evolution the enzyme is a member of the CYB561 protein family Zea mays
evolution the enzyme is a member of the CYB561 protein family Homo sapiens
evolution the enzyme is a member of the CYB561 protein family Schistosoma japonicum
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 Arabidopsis thaliana
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 Mus musculus
additional information 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 Bos taurus
additional information 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 Schistosoma japonicum
additional information 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 Zea mays
additional information 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 Mus musculus
additional information 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 Homo sapiens
additional information 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. The amino acid side chains contributing to the docking of ascorbate on the cytoplasmic surface of the crystallized protein (K77, K81, Y140, R150 and A151) do not constitute a single contiguous region but originate at distant locations of the primary sequence of the protein Arabidopsis thaliana
physiological function b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport Bos taurus
physiological function b-type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Isozyme DCytb is capable of reducing ferric chelates and plays an important role in the iron acquisition of cells Mus musculus
physiological function b-type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Isozyme DCytb is capable of reducing ferric chelates and plays an important role in the iron acquisition of cells Homo sapiens
physiological function b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Plant rTCytb are capable of transporting electrons from cytosolic ASC to extracellular ferric chelates (ferricyanide, ferric-EDTA) in a yeast model system Arabidopsis thaliana
physiological function b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Plant rTCytb are capable of transporting electrons from cytosolic ASC to extracellular ferric chelates (ferricyanide, ferric-EDTA) in a yeast model system Zea mays
physiological function b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. The parasitic trematode Schistosoma japonicum contains a CYB561 protein with ferric chelate reductase activity and localizes to the schistosome tegument, the enzyme might be responsible for iron acquisition in the parasite Schistosoma japonicum