Literature summary for 1.6.3.3 extracted from

Yang, X.; Ma, K.
Characterization of an exceedingly active NADH oxidase from the anaerobic hyperthermophilic bacterium Thermotoga maritima (2007), J. Bacteriol., 189, 3312-3317.

Inhibitors

Inhibitors	Comment	Organism
CuCl2	3 mM, 60% inhibition	Thermotoga maritima
HgCl2	3 mM, 98% inhibition	Thermotoga maritima
hydrocortisone	3 mM, 5% inhibition	Thermotoga maritima
Quinacrine	3 mM, 46% inhibition	Thermotoga maritima
Quinine	3 mM, 23% inhibition	Thermotoga maritima

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
0.042	-	NADH	pH 7.8, 80°C	Thermotoga maritima
0.043	-	O2	pH 7.8, 80°C	Thermotoga maritima

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
46000	-	1 * 54000 + 1 * 46000, SDS-PAGE	Thermotoga maritima
54000	-	1 * 54000 + 1 * 46000, SDS-PAGE	Thermotoga maritima
90000	-	gel filtration	Thermotoga maritima

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
NADH + H+ + O2	Thermotoga maritima	an oxygen-removing system present in Thermotoga maritima is proposed to work in two steps: firstly by converting O2 to hydrogen peroxide by the NADH oxidase, and secondly by reducing the hydrogen peroxide to water by an NADH peroxidase or rubrerythrin or alkyl hydroperoxide reductase	NAD+ + H2O2	-	?

Organism

Organism	UniProt	Comment	Textmining
Thermotoga maritima	-	-	-

Oxidation Stability

Oxidation Stability	Organism
apparently, the enzyme in the cell extract is more resistant to oxygen inactivation than the purified enzyme. Purified enzyme samples exposed to air exhibit a decrease in enzyme activity. The inactivation rate of NADH oxidase activity is dependent on oxygen concentration. The times required for the loss of 50% of the enzyme activity from the purified enzyme are about 20 min and 40 min for oxygen concentrations of 20% (v/v) and 1% (v/v), respectively. However, the times required for the loss of 50% of the enzyme activity from the cell extract aree about 60 min and 360 min for oxygen concentration of 20% (v/v) and 1% (v/v), respectively	Thermotoga maritima

Organism

apparently, the enzyme in the cell extract is more resistant to oxygen inactivation than the purified enzyme. Purified enzyme samples exposed to air exhibit a decrease in enzyme activity. The inactivation rate of NADH oxidase activity is dependent on oxygen concentration. The times required for the loss of 50% of the enzyme activity from the purified enzyme are about 20 min and 40 min for oxygen concentrations of 20% (v/v) and 1% (v/v), respectively. However, the times required for the loss of 50% of the enzyme activity from the cell extract aree about 60 min and 360 min for oxygen concentration of 20% (v/v) and 1% (v/v), respectively

Thermotoga maritima

Purification (Commentary)

Purification (Comment)	Organism
purified under strictly anaerobic conditions	Thermotoga maritima

Specific Activity [micromol/min/mg]

Specific Activity Minimum [µmol/min/mg]	Specific Activity Maximum [µmol/min/mg]	Comment	Organism
144	-	pH 7.0, 80°C	Thermotoga maritima

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
NADH + H+ + O2	an oxygen-removing system present in Thermotoga maritima is proposed to work in two steps: firstly by converting O2 to hydrogen peroxide by the NADH oxidase, and secondly by reducing the hydrogen peroxide to water by an NADH peroxidase or rubrerythrin or alkyl hydroperoxide reductase	Thermotoga maritima	NAD+ + H2O2	-	?
NADH + H+ + O2	the enzyme is highly specific for NADH, no activity with NADPH. Highest activity using O2 as an electron acceptor. Compared to lower activities for benzyl viologen (20%) and 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB, 7%), while no activity is observed when FAD, FMN, or riboflavin is used as the electron acceptor	Thermotoga maritima	NAD+ + H2O2	-	?

Subunits

Subunits	Comment	Organism
dimer	1 * 54000 + 1 * 46000, SDS-PAGE	Thermotoga maritima

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
80	-	-	Thermotoga maritima

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
80	-	t1/2: 100 min	Thermotoga maritima

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
7	-	at 80°C	Thermotoga maritima

Cofactor

Cofactor	Comment	Organism	Structure
FAD	flavoprotein. The enzyme contains 1.9 mol of FAD per mol native enzyme	Thermotoga maritima
NADH	the enzyme is highly specific for NADH, no activity with NADPH	Thermotoga maritima