1.97.1.2 | 1,2,3,5-tetrahydroxybenzene + 1,2,3-trihydroxybenzene = 1,3,5-trihydroxybenzene + 1,2,3,5-tetrahydroxybenzene |
a mechanism is proposed which combines an oxidative hydroxylation with a reductive dehydroxylation via molybdenum cofactor |
437678, 437679 |
1.97.1.2 | 1,2,3,5-tetrahydroxybenzene + 1,2,3-trihydroxybenzene = 1,3,5-trihydroxybenzene + 1,2,3,5-tetrahydroxybenzene |
transfer of the hydroxy group occurs via 2,4,3,4,5-hexahydroxydiphenyl ether as an intermediate. The 1-OH group of pyrogallol coordinates to the MoVI atom of Moco and is oxidized to the orthoquinone form, while H144 accepts the phenolic proton. the 2-OH group of 1,2,3,5-tetrahydroxybenzene adds to the quinone in a Michael-type reaction, which is assisted by proton transfer from D174. The substrate-cocatalyst adduct is tautomerized with the assistance of Y404 as a proton donor. In the last stage, the paraquinone form of the tetrahydroxybenzene is reduced by Mo(IV) |
673091 |