An efficient synthesis of chiral amino acid and peptide alkylamides via CLEC-subtilisin catalyzed coupling and in situ resolution

Crosslinking of enzymes for improved stability and performance

Stabilization of enzymes without diminishing and diluting their activity is crucial for their use as industrial catalysts. One practically proven approach involves crystallization of the enzyme (size 1-200 microm) followed by subsequent crosslinking. In many cases, the resulting crosslinked enzyme crystals exhibit increased storage stability as well as stability in applications. The technology is complementary to protein engineering methods that aim at boosting the inherent stability of the enzyme.

Improving hydrolases for organic synthesis

Improving hydrolases by site-directed mutagenesis continues to be important, but an alternative method - directed evolution - also gains favor. Directed evolution combines random mutagenesis with screening or selection for the desired property. Directed evolution is especially useful for cases like solvent tolerance or thermostability where current theories are inadequate to predict which structural changes will give improvement. Researchers have also recently made significant progress on several practical problems: how to maintain the high activity of proteases and lipases in nonpolar organic solvents, how to resolve amines, and how to efficiently recycle the unwanted enantiomer in kinetic resolutions. Besides the lipases and proteases, researchers are also developing new hydrolases, notably dehalogenases and epoxide hydrolases.