Hydroksylacje enzymatyczne. Zastosowanie preparatywne i mechanizm reakcji z udziałem monooksygenaz cytochromowych P450

Enzymatic conversion of a carbon - hydrogen to a carbon - hydroxyl bond is a key part of the biosynthesis and oxidative metabolism in living organisms from bacteria to humans. Biocatalytic hydroxylations are also widely used in organic synthesis, especially to introduce the desired function to the site of the molecule, which is difficult to obtain by chemical methods. Biocatalytic hydroxylations are most often performed by cytochrome P450 dependent monooxygenases. In a catalytic cycle, one oxygen atom from oxygen molecule is incorporated to water and the other is incorporated into the substrate. Cytochrome P450 is known to catalyze hydroxylations, epoxidations, N-, S-, and O-oxidations, dealkylation, and dehalogenations. The mechanism of the hydroxylation reaction has been explored in the context of synthetic applications, selection of the substrate, and enzyme - substrate interaction. Models involving defined spatial relationships between the mode of substrate-enzyme binding and hydroxylation sites have rationalized the regio- and stereochemistry of hydroxylation. Many of the steps in sequence of the oxidation reactions are well characterized, but the identity of the final oxidant and the reaction mechanism are still not well understood. Recent developments in area biohydroxylation have been focused on the use of new biocatalysts and substrates for C-H activation, the use of recombinant strains of yeast and bacteria expressing desired hydroxylase enzymes.