KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | steady-state kinetics study of enzyme activity in the presence of Cu2+ and with different pre-incubation times, KM values of 0.0096-0.020 mM, overview | Bos taurus |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
extracellular | secretion to milk | Bos taurus | - |
- |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Cu2+ | Cu2+ either stimulates or inhibits xanthine oxidase activity, depending on metal concentration (inhibition above 0.7 mM) and pre-incubation length, the latter also determining the inhibition type. Cu2+-enzyme complex formation is characterized by modifications in xanthine oxidase electronic absorption bands, intrinsic fluorescence, and alpha-helical and beta-sheet content. Apparent dissociation constant values imply high- and low-affinity Cu2+ binding sites in the vicinity of the enzyme's reactive centers, Cu2+ binding to high-affinity sites causes alterations around xanthine oxidase molybdenum and flavin adenine dinucleotide centers, changes in secondary structure, and moderate activity inhibition, binding to low affinity sites causes alterations around all xanthine oxidase reactive centers including FeS, changes in tertiary structure as reflected by alterations in spectral properties, and drastic activity inhibition. Stimulation is attributed to transient stabilization of xanthine oxidase optimal conformation. Potential role of copper in the regulation of xanthine oxidase activity, binding kinetics, detailed overview | Bos taurus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
xanthine + O2 + H2O | Bos taurus | - |
urate + H2O2 | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Bos taurus | - |
- |
- |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
commercial preparation | - |
Bos taurus | - |
milk | - |
Bos taurus | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
xanthine + O2 + H2O | - |
Bos taurus | urate + H2O2 | - |
? |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.5 | - |
assay at | Bos taurus |
General Information | Comment | Organism |
---|---|---|
metabolism | xanthine oxidase, a key enzyme in purine metabolism, produces reactive oxygen species causing vascular injuries and chronic heart failure | Bos taurus |