The use of biocatalysis in the synthesis of labelled compounds

Since most biotransformations are highly chemo-, regio- and stereoselective, they offer many opportunities for the synthesis of compounds that are not easily attainable by classical organic chemistry, The catalytic properties of the cytochrome P450 (CYP450) enzymes of microorganisms can be exploited to produce suitable N-, S- or O-dealkylated precursors, which can be realkylated with the appropriate labelled reagent. These enzymes are also well reported for hydroxylation of activated or nonactivated carbon centres, to produce drug metabolites. Nevertheless, to use such enzymes, a whole cell system is preferred due to the need for cofactor regeneration. Nitrile hydrolysing enzymes also attract attention, due to their ability to selectively hydrolyse nitrile derivatives under mild conditions. The scope of such biotransformations is discussed.