EC Number |
Reaction |
Reference |
---|
1.11.1.18 | RH + HBr + H2O2 = RBr + 2 H2O |
Brings about the bromination of a range of organic molecules, forming stable C-Br bonds. Can also act on iodide ions. The enzymes of this group contain vanadium (V) bound to the active centre. Since the actual halogenating agents are the respective hypohalous acids, vanadium-containing halide peroxidases lack substrate specificity and regioselectivity. |
- |
1.11.1.18 | RH + HBr + H2O2 = RBr + 2 H2O |
proposed states at the bromoperoxidase active site involved in primary product formation and secondary reaction consuming hypobromous acid in the absence of an accepting organic substrate, overview. At the bromoperoxidase II binding site, dihydrogen orthovanadate most likely encounters reactivity in between diffusion-controlled solution chemistry and aligned reactant pairs. According to steady kinetic data, hydrogen peroxide binding to VBrPO(AnII) is one of the rate-determining steps. The energy required for transforming the bromoperoxidase resting state into the peroxo state must be provided by the succeeding step, which is the transfer of a peroxide oxygen atom to bromide. The least negatively charged oxygen in peroxide side-on-4, OP, is the site preferentially approached by bromide in the electronic structure model. Reaction mechanism analysis |
763808 |
1.11.1.18 | RH + HBr + H2O2 = RBr + 2 H2O |
the catalytic cycle imposes changes in the coordination geometry of the vanadium to accommodate the peroxidovanadium(V) intermediate in an environment of as a distorted square pyramidal geometry. During the catalytic cycle, this intermediate converts to a trigonal bipyramidal intermediate before losing the halogen and forming a tetrahedral vanadium-protein intermediate. The catalysis is facilitated by a proton-relay system supplied by the second sphere coordination environment, and the changes in the coordination environment of the vanadium(V) making this process unique among protein catalyzed processes. The active site is very tightly regulated with only minor changes in the coordination geometry. The coordination geometry in the protein structures deviates from that found for both small molecules crystallized in the absence of protein and the reported functional small molecule model compounds. The catalytic mechanism for oxidation of organic substrates catalyzed by haloperoxidases does not change the oxidation state of the vanadium(V) although the vanadium is present as protein bound intermediate with a coordination number altering from four to six |
765199 |