High-Yield Biocatalytic Amination Reactions in Organic Synthesis (original) (raw)

The amino functionality gives important biological activity in pharmaceutical com-pounds. The formation of chiral amines and amino acids can be accomplished by seve-ral chemical routes but enzymatic formation of amines offers many advantages in pre-paring chiral amino compounds or amination of fragile compounds compared to stoi-chiometric or catalytic chemical transformations. Biocatalytic routes to amines primarily use enzymes of the transaminase class (also known as aminotransferases) which transfer the amino function from a donor organic compound to a ketone or aldehyde acceptor. Although known since 1937, the transamination reaction experiences re-newed interest due to the advances in biochemistry and molecular biology and the excellent selectivity of biocatalysts. Other enzymes that have been used to synthesize chiral amines are from the phenylalanine ammonia lyase class that use ammonia as the amino source. The use of recombinant enzymes for the biocatalytic preparation of amines is expanding at a great rate and the range of enzymes revealed in DNA se-quence databases is of the order of tens of thousands. Since a large number of ketone substrates like ketones, hydroxyketones and ketoacids can be made by chemical syn-thesis, the growing toolbox of -, -, -, -, -and -transaminases enable the synthe-sis of various new chemical entities by biocatalytic amination reactions. In order to simplify the isolation and purification of the product, it is useful to drive the amination reaction to completion. The biocatalytic processes that have been developed show different strategies of overcoming the kinetic limitations of the transaminase reactions and show how some enzymes have been used in processes to make large quantities of chiral compounds with amino functionalities.