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MetaCyc Protein Class: an oxidized c-type cytochrome

Synonyms: a ferri c-type cytochrome

Superclasses: a cytochrome a c-type cytochrome
a cytochrome an oxidized cytochrome

Summary:
C-type cytochromes (cytC) are electron-transfer proteins that have one or more heme c groups that are bound to the protein by one or two thioether bonds involving sulfhydryl groups of cysteine residues. C-type cytochromes possess a wide range of properties and function in a large number of different redox processes. In general, the differences in c-type cytochromes among bacteria are much larger than those among animal species. The use of the term term "c-type cytochromes" was introduced to distinguish this family of diverse proteins from the well-characterized mitochondrial protein, which is often referred to as "cytochrome c".

Bacterial c-type cytochromes function in the electron transport chains of bacteria with many different types of energy metabolism, including phototrophs, methylotrophs, denitrifiers, sulfate reducers and the nitrogen-fixers.

The C-type cytochromes have been classified in four classes based on their sequence (reviewed in [Ambler91]):

Class I includes the low-spin soluble cytC of mitochondria and bacteria, with the heme-attachment site towards the N-terminus, and the sixth ligand provided by a methionine residue about 40 residues further on towards the C-terminus. Memebers of this class were further subdivided into the five subclasses, IA to IE, which are named long cytochrome c2, mitochondrial cytochrome c, split-a-band cytochromes c, cytochrome c8 and cytochrome c5, respectively .

Class II includes the high-spin cytochromes c' and various low-spin cytochromes (e.g., Rhodopseudomonas palustris cytochrome c-556). The heme-attachment site is close to the C-terminus and in the low-spin proteins the sixth ligand is a methionine residue close to the N-terminus.

Class III comprises the low redox potential multiple heme cytochromes c3 and c7, with only around thirty residues of amino acid per heme group.

Class IV was created to hold the complex proteins that have other prosthetic groups as well as heme c, such as the flavocytochromes c and the cytochromes cd.

Child Classes: an oxidized cytochrome c-553 (0) , an oxidized cytochrome c2 (0) , an oxidized cytochrome c3 (0) , an oxidized cytochrome c4 (0) , an oxidized cytochrome c550 (0) , an oxidized cytochrome c551 (0) , an oxidized cytochrome c552 (1) , an oxidized cytochrome c554 (0) , an oxidized cytochrome cL (0) , an oxidized cytochrome cm552 (0)

Instances:
formate-dependent nitrite reductase - penta-heme cytochrome c (Escherichia coli K-12 substr. MG1655) ,
SoxE (Paracoccus pantotrophus)

SMILES: CC2(=C(CCC(=O)[O-])C8(=[N+]3([Fe-]46([N+]1(=C(C(C(C)S[a c-type cytochrome])=C(C)C1=CC5(=C(C(C)S[a c-type cytochrome])C(C)=C(C=C23)N45))C=C7(C(C)=C(CCC(=O)[O-])C(N67)=C8))))))

Unification Links: KEGG:C00125

Reactions known to consume the compound:

ammonia oxidation I (aerobic) :
4 an oxidized c-type cytochrome[out] + hydroxylamine[in] + H2O[in] → 4 a reduced c-type cytochrome[out] + nitrite[in] + 5 H+[in]

ammonia oxidation IV (autotrophic ammonia oxidizers) :
4 an oxidized c-type cytochrome[out] + hydroxylamine[in] + H2O[in] → 4 a reduced c-type cytochrome[out] + nitrite[in] + 5 H+[in]
a reduced cytochrome c554 + an oxidized c-type cytochrome → an oxidized cytochrome c554 + a reduced c-type cytochrome

L-ascorbate biosynthesis I (L-galactose pathway) :
L-galactono-1,4-lactone + 2 an oxidized c-type cytochrome → L-ascorbate + 2 a reduced c-type cytochrome + 3 H+

L-ascorbate biosynthesis II (L-gulose pathway) :
L-gulono-1,4-lactone + 2 an oxidized c-type cytochrome → L-ascorbate + 2 a reduced c-type cytochrome + 2 H+

methylglyoxal degradation V :
(S)-lactate + 2 an oxidized c-type cytochrome → pyruvate + 2 a reduced c-type cytochrome + 2 H+

methylglyoxal degradation VI :
(R)-lactate + 2 an oxidized c-type cytochrome → pyruvate + 2 a reduced c-type cytochrome + 2 H+

nitrifier denitrification :
hydroxylamine + an oxidized c-type cytochrome → nitric oxide + a reduced c-type cytochrome + 3 H+

nitrite oxidation :
2 a reduced c-type cytochrome[out] + nitrate[in] + 2 H+[in] ← 2 an oxidized c-type cytochrome[out] + nitrite[in] + H2O[in]

polyvinyl alcohol degradation :
polyvinyl alcohol + n an oxidized c-type cytochrome → oxidized polyvinyl alcohol + n a reduced c-type cytochrome + n H+

sulfide oxidation II (sulfide dehydrogenase) :
hydrogen sulfide + 2 an oxidized c-type cytochrome → S0 + 2 a reduced c-type cytochrome + 2 H+

sulfite oxidation I (sulfite oxidoreductase) :
sulfite + 2 an oxidized c-type cytochrome + H2O → sulfate + 2 a reduced c-type cytochrome + 2 H+

thiosulfate oxidation I (to tetrathionate) :
2 thiosulfate[periplasmic space] + 4 an oxidized c-type cytochrome[periplasmic space] → tetrathionate[periplasmic space] + 4 a reduced c-type cytochrome[periplasmic space] + 2 H+[periplasmic space]

thiosulfate oxidation III (multienzyme complex) :
a [SoxY protein]-S-thiocysteine + 6 an oxidized c-type cytochrome + 3 H2O → a [SoxY protein]-L-cysteine-S-sulfate + 6 a reduced c-type cytochrome + 7 H+
a [SoxY protein]-L-cysteine + thiosulfate + 2 an oxidized c-type cytochrome → a [SoxY protein]-thiocysteine-S-sulfate + 2 a reduced c-type cytochrome + 2 H+

thiosulfate oxidation IV (multienzyme complex) :
a [SoxY protein]-L-cysteine + thiosulfate + 2 an oxidized c-type cytochrome → a [SoxY protein]-thiocysteine-S-sulfate + 2 a reduced c-type cytochrome + 2 H+

Not in pathways:
hydroxylamine + 4 an oxidized c-type cytochrome + oxygen → nitrite + 4 a reduced c-type cytochrome + H2O + H+
2 an oxidized c-type cytochrome[out] + a menaquinol → 2 a reduced c-type cytochrome[out] + a menaquinone + 2 H+[in]
2 an oxidized c-type cytochrome[out] + an electron-transfer-related quinol → 2 a reduced c-type cytochrome[out] + an electron-transfer-related quinone + 2 H+[in]
L-ascorbate + 2 an oxidized c-type cytochrome → L-dehydro-ascorbate + 2 a reduced c-type cytochrome + H+

nicotinate degradation I :
nicotinate + an oxidized cytochrome + H2O → 6-hydroxynicotinate + a reduced cytochrome + 2 H+

Reactions known to produce the compound:

aerobic respiration I (cytochrome c) , aerobic respiration II (cytochrome c) (yeast) , arsenite oxidation I (respiratory) :
4 a reduced c-type cytochrome[out] + oxygen[in] + 8 H+[in] → 4 an oxidized c-type cytochrome[out] + 4 H+[out] + 2 H2O[in]

ammonia oxidation II (anaerobic) , intra-aerobic nitrite reduction :
nitric oxide + an oxidized c-type cytochrome + H2O ← nitrite + a reduced c-type cytochrome + 2 H+

nitrate reduction I (denitrification) :
2 a reduced c-type cytochrome[periplasmic space] + nitrous oxide + 2 H+ → 2 an oxidized c-type cytochrome[periplasmic space] + N2 + H2O

nitrate reduction IV (dissimilatory) :
2 a reduced c-type cytochrome[out] + nitrate[in] + 2 H+[in] → 2 an oxidized c-type cytochrome[out] + nitrite[in] + H2O[in]
ammonia + 6 an oxidized c-type cytochrome + 2 H2O ← nitrite + 6 a reduced c-type cytochrome + 7 H+

nitrate reduction VII (denitrification) :
2 a reduced c-type cytochrome[periplasmic space] + nitrous oxide + 2 H+ → 2 an oxidized c-type cytochrome[periplasmic space] + N2 + H2O
nitric oxide + an oxidized c-type cytochrome + H2O ← nitrite + a reduced c-type cytochrome + 2 H+

nitrifier denitrification :
2 a reduced c-type cytochrome[periplasmic space] + nitrous oxide + 2 H+ → 2 an oxidized c-type cytochrome[periplasmic space] + N2 + H2O
nitric oxide + an oxidized c-type cytochrome + H2O ← nitrite + a reduced c-type cytochrome + 2 H+

Reactions known to both consume and produce the compound:

aerobic respiration I (cytochrome c) , aerobic respiration II (cytochrome c) (yeast) , ammonia oxidation IV (autotrophic ammonia oxidizers) :
2 an oxidized c-type cytochrome[out] + an ubiquinol[CCO-OUT-CCO-IN] + 2 H+[in] ↔ 2 a reduced c-type cytochrome[out] + an ubiquinone[CCO-OUT-CCO-IN] + 4 H+[in]

arsenite oxidation I (respiratory) :
2 a reduced c-type cytochrome[periplasmic space] + arsenate + 3 H+ ← 2 an oxidized c-type cytochrome[periplasmic space] + arsenite + H2O

nitrate reduction I (denitrification) , nitrifier denitrification :
nitrous oxide + 2 an oxidized c-type cytochrome + H2O ↔ 2 nitric oxide + 2 a reduced c-type cytochrome + 2 H+

Not in pathways:
a c-type cytochrome ↔ heme c + an apo c-type cytochrome

In Reactions of unknown directionality:

Not in pathways:
Fe3+ + a reduced c-type cytochrome = Fe2+ + an oxidized c-type cytochrome
hydrogen peroxide + 2 a reduced c-type cytochrome + 2 H+ = 2 an oxidized c-type cytochrome + 2 H2O
2 an oxidized c-type cytochrome + glycine + H2O = 2 a reduced c-type cytochrome + ammonium + glyoxylate + 2 H+
trimethylamine + 2 an oxidized c-type cytochrome + H2O = trimethylamine N-oxide + 2 a reduced c-type cytochrome + 3 H+
ethanol + 2 an oxidized c-type cytochrome = acetaldehyde + 2 a reduced c-type cytochrome + 2 H+
D-mannitol + an oxidized c-type cytochrome = keto-D-fructose + a reduced c-type cytochrome + 2 H+
L-gulono-1,4-lactone + 4 an oxidized c-type cytochrome = L-dehydro-ascorbate + 4 a reduced c-type cytochrome + 4 H+
lupanine + 2 an oxidized c-type cytochrome + H2O = 17-hydroxylupanine + 2 a reduced c-type cytochrome + 2 H+
L-galactono-1,4-lactone + 4 an oxidized c-type cytochrome = L-dehydro-ascorbate + 4 a reduced c-type cytochrome + 4 H+

In Redox half-reactions:
an oxidized c-type cytochrome[out] + e- → a reduced c-type cytochrome[out]

Enzymes inhibited by an oxidized c-type cytochrome, sorted by the type of inhibition, are:

Inhibitor (Mechanism unknown) of: autumnaline cytochrome P-450 oxidase [Nasreen96] , O-methylandrocymbine cytochrome P450 oxidase [Rueffer98]

This compound has been characterized as a cofactor or prosthetic group of the following enzymes: nitric oxide reductase , nicotinate dehydrogenase , alcohol dehydrogenase , nitrate reductase

Gene-Reaction Schematic: ?

Credits:
Revised 18-Jan-2011 by Caspi R , SRI International


References

Ambler91: Ambler RP (1991). "Sequence variability in bacterial cytochromes c." Biochim Biophys Acta 1058(1);42-7. PMID: 1646017

Nasreen96: Nasreen, A., Rueffer, M, Zenk, M.H (1996). "Cytochrome P-450-dependent fromation of isoandrocymbine from autumnaline in colchicine biosynthesis." tetrahedron Letters, 37, 8161-8164.

Rueffer98: Rueffer, M, Zenk, M.H (1998). "Microsome-mediated transformation of O-methylandrocymbine to demecolcine and colchicine." FEBS letters, 438, 111-113.


Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 18.5 on Fri Dec 19, 2014, biocyc14.