TCDB is operated by the Saier Lab Bioinformatics Group
TCIDNameDomainKingdom/PhylumProtein(s)
*5.B.1.1.1









The gp91phox/p22phox NADPH oxidase-associated, cytochrome b558, Nox2. TMS2 is important for stability and electron transfer (Picciocchi et al., 2011). The integral membrane flavocytochrome of Nox 2 transfers an electron from intracellular NADPH to extracellular O2, generating superoxide anion, O2- (Fisher 2009).

Eukaryota
Metazoa
gp91phox (β-chain) of Homo sapiens (Nox2) (P04839)
p22phox (α-chain) of Homo sapiens (P13498)
*5.B.1.1.2









Nucleus/kidney/muscle/endothelial cell superoxide-generating NADPH oxidase (Nox4) (may regulate gene expression) (Cheng et al., 2001; Kuroda et al., 2005). Integrated analyses of heterodimerization, trafficking and catalytic activity have identified determinants for the NOX4-p22phox interaction such as heme incorporation into NOX4 and hot spot residues in TMSs 1 and 4 in p22phox; their effects on NOX4 maturation and ROS generation were analyzed (O'Neill et al. 2018).

Eukaryota
Metazoa
Kidney superoxide-generating NADPH oxidase of Homo sapiens
*5.B.1.1.3









Multiple tissue mitogenic oxidase, subunit 65 (Mox1 or Nox1) (alternative splicing yields a 191 aa protein with H+ channel activity) (Bánfi et al., 2000; Suh et al., 1999)
Eukaryota
Metazoa
Mitogenic oxidase (Nox1) of Homo sapiens
*5.B.1.1.4









Mitogenic NADPH oxidase 3, Nox3 (Cheng et al., 2001). Critical for formation of otoconia, mineral crystals in the inner ear; mutants are defective for motion and gravity sensing (Paffenholz et al., 2004).
Eukaryota
Metazoa
Nox3 of Homo sapiens (Q9HBY0)
*5.B.1.1.5









NADPH oxidase 5 (Nox5) (Cheng et al., 2001)
Eukaryota
Metazoa
Nox5 of Homo sapiens (Q96PH1)
*5.B.1.1.6









Thyroid NADPH oxidase/peroxidase 1 (Dual oxidase 1; Duox1) with two EF band domains, responsive to Ca2+ regulation (De Deken et al., 2000; Edens et al., 2001)
Eukaryota
Metazoa
Duox1 of Homo sapiens (Q9NRD9)
*5.B.1.1.7









Thyroid NADPH oxidase/peroxidase 2 (Dual oxidase 2; Duox2) with two EF band domains, responsive to Ca2+ regulation (De Deken et al., 2000; Edens et al., 2001)
Eukaryota
Metazoa
Duox2 of Homo sapiens (Q9NRD8)
*5.B.1.1.8









Respiratory burst oxidase proteins A-F
Eukaryota
Viridiplantae
Respiratory burst oxidase A of Arabidopsis thaliana
*5.B.1.1.9









Respiratory burst oxidase homologue F, RBOHF, of 944 aas and 6 TMSs.  Calcium-dependent NADPH oxidase that generates superoxide. Generates reactive oxygen species (ROS) during incompatible interactions with pathogens and is important in the regulation of the hypersensitive response (HR). Involved in abscisic acid-induced stomatal closing and in UV-B and abscisic acid ROS-dependent signaling (Song et al. 2006; Desikan et al. 2006; Kwak et al. 2003).

Eukaryota
Viridiplantae
RBOHF of Arabidopsis thaliana (Mouse-ear cress)
*5.B.1.2.1









NADPH oxido-reductase of 450 aas and 7 TMSs.  These proteins have been characterized in prokaryotes as well as eukaryotes (Hajjar et al. 2017).

Bacteria
Proteobacteria
Putative oxido-reductase of Vibrio cholerae
*5.B.1.2.2









Uncharacterized oxidoreductase of 445 aas and 6 N-terminal TMSs.

Bacteria
Actinobacteria
Putative oxidoreductase of Streptomyces sp.
*5.B.1.2.3









Ferric reductase like transmembrane component of 220 aas and 6 TMSs.

Bacteria
Bacteroidetes
Ferric reductase of Thermophagus xiamenensis
*5.B.1.2.4









Uncharacterized protein of 441 aas and 6 N-terminal TMSs.

Bacteria
Planctomycetes
UP of Planctomycetes bacterium
*5.B.1.2.5









Uncharacterized protein of 215 aas and 6 TMSs.

Bacteria
Candidatus Curtissbacteria
UP of Candidatus Curtissbacteria bacterium
*5.B.1.2.6









Uncharacterized protein of 205 aas and 6 TMSs.

Bacteria
Candidatus Saccharibacteria
UP of Candidatus Saccharibacteria bacterium
*5.B.1.2.7









Uncharacterized protein of 210 aas and 6 TMSs.

Bacteria
Candidatus Nomurabacteria
UP of Candidatus Nomurabacteria bacterium
*5.B.1.2.8









Uncharacterized protein of 222 aas and 6 TMSs.

Bacteria
Firmicutes
UP of Alicyclobacillus sendaiensis
*5.B.1.2.9









Uncharacterized ferric reductase domain protein transmembrane component of 287 aas and 6 TMSs.

Bacteria
Candidatus Moranbacteria
UP of Candidatus Moranbacteria bacterium
*5.B.1.3.1









CDP-6-deoxy-delta-3,4-glucoseen reductase (Han et al. 1990).

Bacteria
Proteobacteria
CDP-6-deoxy-delta-3,4-glucoseen reductase of Yersinia pseudotuberculosis
*5.B.1.3.2









Phenol hydroxylase (Yu et al. 2011).

Bacteria
Proteobacteria
Phenol hydroxylase of Acinetobacter calcoaceticus
*5.B.1.4.1









Ferric reductase/oxidase, FRO1
Eukaryota
Viridiplantae
FRO1 of Arabidopsis thaliana
*5.B.1.4.2









Iron chelate reductase, Fox1 (La Fontaine et al., 2002)
Eukaryota
Viridiplantae
Fox1 of Chlamydomonas reinhardtii (ABM66085)
*5.B.1.4.3









Fro1, ferric chelate reductase (Enomoto et al., 2007).
Eukaryota
Viridiplantae
Fro1 of Lycopersicon esculentum (Q6EMC0)
*5.B.1.4.4









Ferric reduction oxidase 2, Fro2 or Frd1, of 725 aas. Flavocytochrome that transfers electrons across the plasma membrane to reduce ferric iron chelates and form soluble ferrous iron in the rhizosphere. May be involved in the delivery of iron to developing pollen grains. Acts also as a copper-chelate reductase. Involved in glycine betaine-mediated chilling tolerance and reactive oxygen species accumulation (Robinson et al. 1999; Wu et al. 2005; Connolly et al. 2003; Einset et al. 2008).

Eukaryota
Viridiplantae
Fro2 of Arabidopsis thaliana (Mouse-ear cress)
*5.B.1.5.1









Plasma membrane Fe3+ and Cu2+ reductase, Fre1 (transfers electrons from NADPH in the cytoplasm to Fe3+ and Cu2+ in the extracellular millieu) (Rees and Thiele, 2007).  Thus, it, as well as Fre2 (TC# 5.B.1.7.2), mediate the reductive uptake of Fe3+-salts and Fe3+ bound to catecholate or hydroxamate siderophores. Fe3+ is reduced to Fe2+, which then dissociates from the siderophore and can be imported by the high-affinity Fe2+ transport complex in the plasma membrane. Also participates in Cu2+ reduction and Cu+ uptake (Dancis et al. 1992; Hassett and Kosman 1995; Lesuisse et al. 1996; Georgatsou et al. 1997; Shi et al. 2003).

Eukaryota
Fungi
Fre1 of Saccharomyces cerevisiae
(P32791)
*5.B.1.5.2









Vacuolar Fe3+ and Cu2+ reductase, Fre6 (transfers electrons from NADPH in the cytoplasm to Cu2+ in the vacuole) (Rees and Thiele, 2007).
Eukaryota
Fungi
Fre6 of Saccharomyces cerevisiae
(Q12473)
*5.B.1.5.3









Fre2 Fe3+/Cu2+ oxidoreductase of 711 aas; similar in catalytic function to Fre1 (TC# 5.B.1.5.1), but induced only by Fe3+, not Cu2+ (Georgatsou et al. 1997; Yun et al. 2001).

Eukaryota
Fungi
Fre2 of Saccharomyces cerevisiae
*5.B.1.5.4









Ferric reductase, FreB of 582 aas and 7 TMSs (Rehman et al. 2017).

Eukaryota
Fungi
FreB of Verticillium dahliae (Verticillium wilt)