Abstract
Enzymatic halogenation and haloperoxidation are unusual processes in biology; however, a range of halogenases and haloperoxidases exist that are able to transfer an aliphatic or aromatic C–H bond into C–Cl/C–Br. Haloperoxidases utilize hydrogen peroxide, and in a reaction with halides (Cl−/Br−), they react to form hypohalides (OCl−/OBr−) that subsequently react with substrate by halide transfer. There are three types of haloperoxidases, namely the iron-heme, nonheme vanadium, and flavin-dependent haloperoxidases that are reviewed here. In addition, there are the nonheme iron halogenases that show structural and functional similarity to the nonheme iron hydroxylases and form an iron(IV)-oxo active species from a reaction of molecular oxygen with α-ketoglutarate on an iron(II) center. They subsequently transfer a halide (Cl−/Br−) to an aliphatic C–H bond. We review the mechanism and function of nonheme iron halogenases and hydroxylases and show recent computational modelling studies of our group on the hectochlorin biosynthesis enzyme and prolyl-4-hydroxylase as examples of nonheme iron halogenases and hydroxylases. These studies have established the catalytic mechanism of these enzymes and show the importance of substrate and oxidant positioning on the stereo-, chemo- and regioselectivity of the reaction that takes place.
Highlights
Nature utilizes enzymes for essential biochemical transformations, whereby compounds that cannot be taken in from food are synthesized
Not common in nature, there are a number of enzymes linked to halogenation and haloperoxidase reaction mechanisms, whereby an aliphatic or aromatic C–H bond is replaced by C–X (X = Cl, Br, I)
We tested several active we tested several active site mutants, where, e.g., Trp140 and Trp243 were replaced by smaller residues
Summary
Nature utilizes enzymes for essential biochemical transformations, whereby compounds that cannot be taken in from food are synthesized. These halogens onto compounds for the pharmaceutical, agrochemical, and materials industries, several methods, rooted in organic chemistry, have been created These methods require materials which are toxic to the environment and result in poor selectivity, and despite steps taken to address these issues, for example, using directing groups to control the selectivity by controlling the position of functionalization, there is still a need to develop more sustainable ways of selectively halogenating compounds. One attractive of doing this to use which methods require materials which are toxicmethod to the environment andisresult in halogenases, poor selectivity, and are enzymes which selectively halogenate compounds during the production of secondary metabolites, despite steps taken to address these issues, for example, using directing groups to control the to install halogens onto natural synthetic scaffolds. Classification of the halogenases according to the nature of their Radical active halogenating agent
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
