An HASApf-redoxin complex causing asymmetric catalytic oxidation via the regenerative formation of a reactive oxygen...

A PP (pea)-HASApf-redoxin complex eluted from encapsulated PP gel with aeration displays asymmetric oxidation activity over 200 times greater than that of a similar protein expressed by E. coli cells. The intermediate spin, identified in the ESR spectrum, appears at g = 4.3 and g = 2.0, suggesting that an iron electron-transfer system for the asymmetric oxidation of secondary alcohols may be successfully created by the PP-HASApf-redoxin complex (39 kDa). FTIR experiments provided values νs(SO2) ≈ 950-1050 cm(-1) and νas(SO2) ≈ 1100-1200 cm(-1) for metal-bound sulfinate S-O and Fe-O vibrations. The sulfur and iron detected by physicochemical inspection (IC/ICP-AES) may facilitate the electron transport of a sulfate-iron complex (e.g., rubredoxin (6 kDa) or ferredoxin (9 kDa)) to the HASApf (21 kDa). The observations are consistently acceptable; i.e., the oxygen-driven PP-HASApf-redoxin complex functions regenerate via the successive asymmetric catalytic event - Fe(ii) + O2 → Fe(iii)-O-O(-) → Fe(iv) = O (oxidizing rac- or rac-) → Fe(ii) + H2O. Therefore, the use of a raw biomaterial as a PP-HASApf-redoxin complex-catalytic system for asymmetric oxidation is an important novelty, despite the apparent difficulties in working with pure dehydrogenase enzymatic/redox-cofactor systems for biotransformation.