Literature summary for 1.1.3.9 extracted from
Ikemoto, H.; Mossin, S.; Ulstrup, J.; Chi, Q.
Probing structural and catalytic characteristics of galactose oxidase confined in nanoscale chemical environments (2014), RSC Adv., 4, 21939-21950 .
No PubMed abstract available
Activating Compound
Activating Compound |
Comment |
Organism |
Structure |
K3[Fe(CN)6] |
- |
Hypomyces rosellus |
|
Protein Variants
Protein Variants |
Comment |
Organism |
additional information |
the enzyme is immobilized in a nanoscale chemical environment provided by mesoporous silicas (MPS). Two types of MPS, i.e. SBA-15 and MCF, are synthesized and used to accommodate GAOX. SBA-15-ROD are rod-shaped particles with periodically ordered nanopores (9.5 nm), while MCF has a mesocellular foam-like structure with randomly distributed pores (23 nm) interconnected by smaller windows (8.8 nm). GAOX is non-covalently bound to SBA-15-ROD, while it is covalently immobilized on MCF. Relatively high loadings in the range of 50-60 mg/g are achieved. The catalytic kinetics is reduced, mainly attributed to the diffusion limitation of substrate and product in the nanoscale channels. The apparent KM of the enzyme is largely unchanged upon immobilization, while the turnover number (kcat) is slightly reduced. The overall catalytic efficiency, represented by the ratio of kcat/KM, is retained around 70% and 60% for SBA-15 and MCF immobilization, respectively. The thermal resistance is enhanced up to 60°C, but with no further enhancement above 60°C. Three-dimensional structure analysis of immobilzed enzyme, overview |
Hypomyces rosellus |
Localization
Localization |
Comment |
Organism |
GeneOntology No. |
Textmining |
extracellular |
the enzyme is secreted |
Hypomyces rosellus |
- |
- |
Metals/Ions
Metals/Ions |
Comment |
Organism |
Structure |
Cu2+ |
metalloenzyme, copper catalytic centre of immobilzed enzyme, overview. The Cu ion is coordinated to two tyrosines (Tyr272 and Tyr495), two histidines (H496 and H581) and a solvent ligand (water), forming the inner coordination sphere (a type 2 centre) in the active site |
Hypomyces rosellus |
|
Natural Substrates/ Products (Substrates)
Natural Substrates |
Organism |
Comment (Nat. Sub.) |
Natural Products |
Comment (Nat. Pro.) |
Rev. |
Reac. |
D-galactose + O2 |
Hypomyces rosellus |
- |
D-galacto-hexodialdose + H2O2 |
- |
? |
|
Organism
Organism |
UniProt |
Comment |
Textmining |
Hypomyces rosellus |
P0CS93 |
i.e. Fusarium graminearum |
- |
Purification (Commentary)
Purification (Comment) |
Organism |
the commercially availbale enzyme is further purified by gel filtration |
Hypomyces rosellus |
Source Tissue
Source Tissue |
Comment |
Organism |
Textmining |
commercial preparation |
lyophilzed powder |
Hypomyces rosellus |
- |
Substrates and Products (Substrate)
Substrates |
Comment Substrates |
Organism |
Products |
Comment (Products) |
Rev. |
Reac. |
D-galactose + O2 |
- |
Hypomyces rosellus |
D-galacto-hexodialdose + H2O2 |
- |
? |
|
D-galactose + O2 |
the overall catalytic reaction can be split into two half-reactions, i.e. oxidative and reductive half-reactions |
Hypomyces rosellus |
D-galacto-hexodialdose + H2O2 |
- |
? |
|
Subunits
Subunits |
Comment |
Organism |
monomer |
1 * 68000, SDS-PAGE |
Hypomyces rosellus |
More |
three-dimensional structure analysis |
Hypomyces rosellus |
Synonyms
Synonyms |
Comment |
Organism |
GAOX |
- |
Hypomyces rosellus |
Temperature Optimum [°C]
Temperature Optimum [°C] |
Temperature Optimum Maximum [°C] |
Comment |
Organism |
25 |
- |
assay at |
Hypomyces rosellus |
pH Optimum
pH Optimum Minimum |
pH Optimum Maximum |
Comment |
Organism |
7 |
- |
assay at |
Hypomyces rosellus |
pI Value
Organism |
Comment |
pI Value Maximum |
pI Value |
Hypomyces rosellus |
about |
- |
12 |
General Information
General Information |
Comment |
Organism |
additional information |
enzyme active site structure analysis of immobilzed enzyme, overview. In the active site region, the Cu ion is coordinated to two tyrosines (Tyr272 and Tyr495), two histidines (H496 and H581), and a solvent ligand (water), forming the inner coordination sphere (a type 2 centre). Importantly, Tyr272 is covalently bonded to Cys228 via a thioether bond and its radical form (Tyrc272) serves as a catalytic cofactor (i.e. the second redox site). Trp290 stacks over the Cys228 side chain and plays an essential role in generating Tyrc272 radicals for maintaining the enzyme catalytic cycles. Three-dimensional structure analysis |
Hypomyces rosellus |