Saturday, October 29, 2011
Hall 1-2 (San Jose Convention Center)
Biocatalysts are increasingly used in industry to create enantiomerically pure compounds. In 2000, 35% of pharmaceutical intermediates were chiral compounds, and this number is expected to increase to 70% in 2010 [1]. Nowadays, chiral compounds are produced through difficult chemical syntheses often requiring the use of harsh solvents and complicated separations. Enzymes have unmatched selectivity and are able to carry out reactions under mild conditions without the need of organic solvents. By using biocatalysis, enzymes can be used to produce enantiomerically pure compounds avoiding the difficulties of current production methods. Unfortunately, reactions of industrial interest lack an enzymatic route, specifically the direct synthesis of chiral amines from a prochiral ketone. To create a successful NADH-dependent amine dehydrogenase capable of producing chiral amines, the natural amino acid dehydrogenase (Phenylalanine Dehydrogenase) must be mutated at the residues responsible for forming the ligand binding pocket, while avoiding those with a role in enzymatic function. With this biocatalyst, we will be able to produce a chiral amine by direct reductive amination from the prochiral ketone and ammonia. New methods of protein engineering, applied rational design guided by mechanistic and structural knowledge. Once beneficial mutations have been discovered, the protein variants need to be purified and characterized for properties such as KM, Vmax and KI parameters. Specific activity toward a range of substrates was also studied.
[1] Pollard, D.J. and J.M. Woodley, Biocatalysis for pharmaceutical intermediates: the future is now. Trends in Biotechnology, 2007. 25(2): p. 66-73.