Some New Developments in Reductive Amtnation with Cofactor Regeneration

Abstract
The substrate specificity of LeuDH from Bacillus stearothermophilus and of PheDH from Rhodococcus sp. was investigated and found to be complementary. LeuDH from different organisms have remarkably similar substrate specificity. During optimization of the synthesis of L-tert-leucine, two byproducts (N-α-pivaloyl-tert-leucine amide (I) and 2,4-di-tert-butyl-5-hydroxyimidazol (II)) were found and identified which originate from chemical reactions of keto acid and ammonia.