(A) Alcohol amination cascade with internal cofactor recycling employing purified enzymes. (B) E. coli cell transformed with the two plasmids (pET28b and pETDuet) harboring the genes for the enzymes involved in the alcohol amination cascade. The optimal cellular redox-balance is maintained by the addition of minimal amount of glucose, which partially produces NADH by cellular metabolism. (C) SDS-PAGE gels showing balanced expression levels of proteins in E. coli containing pETDuet (Strain 1, left picture) or pETDuet and pET28b (Strain 3, right picture) plasmids, respectively. Lanes numbered 1 and 2 show the samples prior to induction with IPTG and after protein expression, respectively. (D) The substrates explored in this study.