Although fluorine in the form of fluoride minerals is the most abundant halogen in the Earth's crust, only 12 naturally occurring organofluorine compounds have so far been found¹, and how these are biosynthesized remains a mystery². Here we describe an enzymatic reaction that occurs in the bacterium Streptomyces cattleya and which catalyses the conversion of fluoride ion and S-adenosylmethionine (SAM) to 5'-fluoro-5'-deoxyfluoroadenosine (5'-FDA). To our knowledge, this is the first fluorinase enzyme to be identified, a discovery that opens up a new biotechnological opportunity for the preparation of organofluorine compounds.

1. School of Chemistry and Centre for Biomolecular Sciences, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
2. Microbial Biochemistry Section, Department of Food Science, The Queen's University of Belfast, Newforge Lane, Belfast BT9 SPX, UK

Correspondence to: David O'Hagan¹ e-mail: Email: do1@st-andrews.ac.uk