Cloned (Comment) | Organism |
---|---|
recombinant barley oxalate oxidase expressed in Pichia pastoris (X33) | Hordeum vulgare |
Protein Variants | Comment | Organism |
---|---|---|
S49A | nonglycosylated oxalate oxidase is produced by site-directed mutagenesis (S49A) | Hordeum vulgare |
General Stability | Organism |
---|---|
based on the absoption changes at 325 nm, it is possible to estimate the half-life of the Mn5+ species at room temperature: t1/2 = 42 h (pH 4) or 95 h (pH 7) | Hordeum vulgare |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
additional information | the presence of either superoxide dismutase or manganese catalase in the assay mixture dramatically accelerates turnover inactivation and resultes in a vanishingly small Vs value in the steady state | Hordeum vulgare |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.78 | - |
oxalate | oxalate oxidase activity is measured by oxygen uptake assay with a Clark oxygen electrode in a thermostated cell (25°C). The Km evalutated from initial velocity data exhibits a strong pH dependence with limiting slopes (versus pH) of 0.9 (below pH 4) and 1.5 (above pH 4) | Hordeum vulgare |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mn2+ | titration of periodate-oxidized oxalate oxidase with hydroxylamine completely eliminates the visible absorption, forming a homogeneous Mn2+ form of the enzyme. The fully reduced Mn2+ form lacks any detectable oxidase activity, reoxidation substantially restores the maximum activity. | Hordeum vulgare | |
Mn3+ | treatment of the periodate-oxidized enzyme with ascorbate results in a substantioal decrease in absorption, forming a complex that is spectroscopically identified as a Mn3+ species. Mn3+ form has a 5fold higher specific activity than native recombinant oxalate oxidase. | Hordeum vulgare | |
Mn5+ | titration of oxalate oxidase with sodium periodate results in nearly stoichometric oxidation of the enzyme to an intensely colored yellow complex, whose complete spectroscopic characterization lead to assignment to a superoxidized Mn5+ complex. Treatment of Mn2+ S49A oxalate oxidase generates the same yellow species as the glycosylated wild type enzyme. Mass spectra of isolated and periodate-treated oxalate oxidase are virtually identical, demonstating that no protein oxidation occurred. Peroxidate oxidation increases the specific activity about 5fold. | Hordeum vulgare |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Hordeum vulgare | - |
barley | - |
Purification (Comment) | Organism |
---|---|
- |
Hordeum vulgare |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
additional information | - |
the effect of the isotopic composition of the solvent is investigated by assaying oxalate oxidase in buffer prepared form H2O/D20 mixtures.The limiting values of Vs (steady state rate) lead to an estimate of the overall solvent kinetic isotope effect kH2O/kD2O = 8.5 (k=burst rate constant) | Hordeum vulgare |
additional information | - |
Vimax (initial maximum velocity) is nearly independent of pH over the range from pH 3 to 5 | Hordeum vulgare |
21.9 | - |
native wild type oxalate oxidase | Hordeum vulgare |
94 | - |
native S49A oxalate oxidase | Hordeum vulgare |
139 | - |
periodate-oxidized oxalate oxidase, Mn5+ content 100% | Hordeum vulgare |
156 | - |
ascorbate-reduced oxalate oxidase, Mn3+ content above 95% | Hordeum vulgare |
Turnover Number Minimum [1/s] | Turnover Number Maximum [1/s] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
9.7 | - |
oxalate | oxalate oxidase activity is measured by oxygen uptake assay with a Clark oxygen electrode in a thermostated cell (25°C) | Hordeum vulgare |
pH Minimum | pH Maximum | Comment | Organism |
---|---|---|---|
2.5 | 6 | the catalytic efficiency (Vmax/Km) increases continuously to lower pH | Hordeum vulgare |