Purification and properties of an aryl‐alcohol dehydrogenase from the white‐rot fungus Phanerochaete chrysosporium

Abstract

An intracellular aryl‐alcohol dehydrogenase (previously referred to as aryl‐aldehyde reductase) was purified from the white‐rot fungus Phanerochaete chrysosporium. The enzyme reduced veratraldehyde to veratryl alcohol using NADPH as a cofactor. Other aromatic benzaldehydes were also reduced, but not aromatic ketones. Methoxy‐substituted rings were better substrates than hydroxylated ones. The enzyme was also able to reduce a dimeric aldehyde (4‐benzyloxy‐3‐methoxybenzaldehyde). The highest reduction rate was measured when 3,5‐dimethoxybenzaldehyde was used as a substrate. On SDS/PAGE the purified enzyme showed one major band with a molecular mass of 47 kDa, whereas gel filtration suggested a molecular mass of 280 kDa. Polyclonal antibodies raised against the gel purified 47‐kDa protein were able to immunoprecipitate the aryl‐alcohol dehydrogenase indicating that its activity possibly resides entirely in this protein fragment. The pI of the enzyme was 5.2 and it was most active at pH 6.1. The aryl‐alcohol dehydrogenase was partially inhibited by typical oxidoreductase inhibitors.