Revealing Cutinases’ Capabilities as Enantioselective Catalysts

The specific activity and enantioselectivity of immobilized cutinases from Humicola insolens (HiC) and Aspergillus oryzae (AoC) were compared with those of Lipase B from Candida antarctica (CALB) for a series of 1-phenylethanol (1-PEA) structural analogues. The aim was to understand their catalytic behavior by rationally studying three structural elements of the substrates: the length of the alkyl chain, the position of methylation of the aromatic ring, and the aromatic character of the ring. All enzymes were immobilized on the macroporous support Lewatit VP OC 1600 at loadings of ∼10% w/w. Docking studies revealed structural features of the enzymes that led to activity differences. All three enzymes exhibit (R)-selectivity. AoC, due to its more open and accessible active site, possesses high activity that exceeds in most cases that of HiC and CALB. By increasing the substrate’s alkyl chain length from methyl to n-propyl, the activity for the (R)-enantiomer of all three enzymes decreased significantly (≥7...