Enzymatic fluorination in Streptomyces cattleya takes place with an inversion of configuration consistent with an SN2 reaction mechanism.

The stereochemical course of the recently isolated fluorination enzyme from Streptomyces cattleya has been evaluated. The enzyme mediates a reaction between the fluoride ion and S- adenosyl-L-methionine (SAM) to generate 5'-fluoro-5'-deoxyadenosine (5'-FDA). Preparation of (5'R)-[5-(2)H(1)]-ATP generated (5'R)-[5-(2)H(1)]-5'-FDA in a coupled enzyme assay involving SAM synthase and the fluorinase.

The observation of a large gauche preference when 2-fluoroethylamine and 2-fluoroethanol become protonated.

The energies of the gauche and anti conformers of 2-fluoroethylamine, 2-fluoroethanol and their protonated analogues are calculated using density functional theory. Unlike the non protonated systems, the protonated systems show a strong gauche effect where the C-F and the C-(+)NH(3) or C-F and C-(+)OH(2) bonds are gauche rather than anti to each other. Single crystal X-ray diffraction studies of 2-fluoroethylammonium compounds identify the same conformational preference.

Identification of 5-fluoro-5-deoxy-D-ribose-1-phosphate as an intermediate in fluorometabolite biosynthesis in Streptomyces cattleya.

5'-Fluoro-5'-deoxy-D-ribose-1-phosphate (FDRP) is identified as a biosynthetic intermediate during fluorometabolite biosynthesis in Streptomyces cattleya.

Isolation and characterisation of 5'-fluorodeoxyadenosine synthase, a fluorination enzyme from Streptomyces cattleya.

5'-fluorodeoxyadenosine synthase, a C-F bond-forming enzyme, has been purified from Streptomyces cattleya. The enzyme mediates a reaction between inorganic fluoride and S-adenosyl-L-methionine (SAM) to generate 5'-fluoro-5'-deoxyadenosine. The molecular weight of the monomeric protein is shown to be 32.

Biochemistry: biosynthesis of an organofluorine molecule.

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 found, and how these are biosynthesized remains a mystery. 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.

The 3-methylaspartase reaction probed using 2H- and 15N-isotope effects for three substrates: a flip from a concerted to a carbocationic amino-enzyme elimination mechanism upon changing the C-3 stereochemistry in the substrate from R to S.

The mechanisms of the elimination of ammonia from (2S,3S)-3-methylaspartic acid, (2S)-aspartic acid and (2S,3R)-3-methylaspartic acid, catalysed by the enzyme L-threo-3-methylaspartase ammonia-lyase (EC 4.3.1.

Mechanism of 3-methylaspartase probed using deuterium and solvent isotope effects and active-site directed reagents: identification of an essential cysteine residue.

The mechanism of the L-threo-3-methylaspartate ammonia-lyase (EC 4.3.1.

An examination of some derivatives of S-nitroso-1-thiosugars as vasodilators.

A number of S-nitrosated compounds derived from 1-thiosugars (glucose, galactose, xylose, maltose, and lactose) have been prepared and characterized. Most of the compounds obtained were unstable either as solids or in solution. However, S-nitroso-1-thio-2,3,4,6-tetra-O-acetylglucopyranose was stable enough to examine as a vasodilator using an isolated rat tail artery model.