Abstract: Halogenated molecules are widely distributed in the biosphere with a variety of uses in pharmacology. Halogenating enzymes have been identified for the biosynthesis of halogenated compounds by catalyzing the formation of carbonhalogen bond. According to their different reaction mechanisms, halogenating enzymes are divided into two main groups, haloperoxidases and flavin-dependent halogenases. In addition, other halogenases including non-heme FeII􊄯α-ketoglutarate (αKG)-dependent halogenases, methyl halide transferases and fluorinase were recently discovered. This review concentrates on the occurrence , mechanism and biocatalytic potential of the halogenating enzymes that are currently known. The biological importance of halogenating enzymes in biohalogenation has aroused wide concern. Meanwhile, using modern biotechnology, for example , combinatorial biosynthesis and directed evolution , the prospects for generating halogenated derivatives of valuable natural products would therefore appear very bright.

Key words: Halogenase