Biocatalysis – Fluorinase

Mechanism + Description

Fluorinase acts on SAM like substrates introducing F- via an SN2 reaction.

General comments

Fluorinase and related enzymes are transferases that can deliver fluoride anion to certain substrates via an S_N2 type mechanism. The number of substrates accepted by these enzymes are growing, but is somewhat limited by certain key structural requirements of the enzyme. The mild conditions given by enzyme catalysis make fluorinase catalysis attractive for sensitive substrates, especially when ¹⁸F is to be introduced.

Enzyme-catalysed electrophilic fluorination is not known. The very high oxidation potential of F₂ or F⁺ equivalents mean that the protein or even water would be oxidised before any substrate, even if enzymic oxidation of F^– where thermodynamically feasible.

Key references

Beilstein TV: The flourinase enzyme as a tool for flourine-18 incorporation.

O’Hagan, D.; Deng, H. Enzymatic Fluorination and Biotechnological Developments of the Fluorinase. Chem. Rev. 2015, 115, 634–649.

Relevant scale up examples

None found.