Application of a Heme-Binding Protein Eluted from Encapsulated Biomaterials to the Catalysis of Enantioselective Oxidation

A protein complex (PX) eluted from an encapsulated pea protein (PP) under aeration can be used as two types of biocatalysts: a polyethylene glycol (PEG) (1000/4000 = 2/1)-aggregated PX (AGPX) and a glutaraldehyde (GA)/compound-modified PX (CMPX). These biocatalysts have the following functional activities: AGPX can catalyze the oxidation of rac-1-(6-methoxynaphthalen-2-yl)ethanol (rac-1) to the corresponding ketone (∼95% chemical yield) via the selective oxidation of (S)-(+)-1, leaving highly enantiopure (R)-(−)-1 (>99% ee; ∼50% chemical yield); CMPX can catalyze the kinetic resolution of (S)-(+)-1 ((S)-naproxen precursor, >99% ee, ∼50% chemical yield) via the selective oxidation of (R)-(−)-1 to the corresponding ketone. Both reactions occur in the absence of an added cofactor (e.g., NAD(P)) in aqueous media. The specific activities of AGPX and CMPX were determined to be 0.8 ± 0.03 mU (mean ± SD) and 0.6 ± 0.02 mU (mean ± SD), respectively, and the exact nature of the species engaged in the key reaction w...