Application | Comment | Organism |
---|---|---|
analysis | galactose oxidase is an important component in electrochemical biosensors of galactose that are used for various biotechnology applications | Hypomyces rosellus |
Crystallization (Comment) | Organism |
---|---|
analysis of crystal structure, PDB ID 1GOF, of the processed (cofactor formed) Cu(II) site reveals the active site ligation. Residues His496, His581, cysteinylated-Tyr272, and an acetate ion form the four equatorial ligands. In the structure of Cu(II)-GO crystallized without acetate, PDB ID 1GOG, the fourth equatorial position is occupied by a weakly bound water. A second tyrosine, Tyr495, occupies an axial position with a Cu-O 2.62.7 A distance in these structures. Spectroscopical characterization of the geometric structure of the pre-processed Cu(I) active site using Cu K-edge X-ray absorption spectroscopy. Molecular modeling of the pre-processed Cu(I)-galactose oxidase active site and biogenesis reaction coordinate | Hypomyces rosellus |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
extracellular | the enzyme is secreted | Hypomyces rosellus | - |
- |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
copper | galactose oxidase is a copper-dependent enzyme that accomplishes 2e- substrate oxidation by pairing a single copper with an unusual cysteinylated tyrosine (Cys-Tyr) redox cofactor. The active site of GO contains only a single Cu . Post-translational biogenesis of Cys-Tyr is copper- and O2-dependent, resulting in a self-processing enzyme system. Cu(I) and Cu(II) enzyme states, Cu(I) active site modeling: on model uses the crystal structure of apo pre-processed GO (PDB ID 2VZ1) with Cu(I) manually added as the starting structure, while the other uses the crystal structure of processed Cu(II)-GO (PDB ID 1GOF) with the Cys-Tyr crosslink manually removed. In both cases, the model includes Cys228, Tyr272, Tyr495, His496 and His581 residues. Cu(I) activation mechanism, overview | Hypomyces rosellus |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
D-galactose + O2 | Hypomyces rosellus | - |
D-galacto-hexodialdose + H2O2 | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Hypomyces rosellus | - |
- |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
proteolytic modification | to form mature active enzyme, the expressed pre-processed protein undergoes a series of post-translational modifications to remove leader peptides, and, most importantly, crosslink cysteine with tyrosine to form the Cys-Tyr cofactor | Hypomyces rosellus |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
D-galactose + O2 | - |
Hypomyces rosellus | D-galacto-hexodialdose + H2O2 | - |
? |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
Cys-Tyr cofactor | the active-site Cu is coordinated by a unique cysteinylated tyrosine (Cys-Tyr) ligand that serves as a second redox-active cofactor. Post-translational biogenesis of Cys-Tyr is copper- and O2-dependent, resulting in a self-processing enzyme system. Mechanism of cofactor biogenesis in galactose oxidase, overview. The role of cysteinylation (as well asPi-stacking of an adjacent conserved Trp) is to stabilize the (Cys-Tyr)radical and allow its function as a redox cofactor at a more biologically accessible potential. In turnover the Cu/(Cys-Tyr) unit accomplishes 2e- redox by shuttling between CuI/(Cys-Tyr)- and CuII/(Cys-Tyr) radical states in a ping-pong type mechanism | Hypomyces rosellus |
General Information | Comment | Organism |
---|---|---|
additional information | active site structure, analysis of crystal structure PDB ID 1GOF, overview. Molecular modeling of the pre-processed Cu(I)-galactose oxidase active site and biogenesis reaction coordinate | Hypomyces rosellus |
physiological function | galactose oxidase catalyzes the 2e- oxidation of primary alcohols to aldehydes and the enzyme may also be capable of the subsequent slower 2e- oxidation to carboxylic acids. Each of these reactions is coupled to the 2e- reduction of O2 to H2O2. The native substrate of the enzyme is D-galactose, but a broad range of other sugar and aromatic alcohol substrates are also active, which has led to the proposal that the physiological role of GO is the generation of H2O2, perhaps as a defense against pathogenic organisms | Hypomyces rosellus |