STUDIES ON THE POLYVINYL-ALCOHOL) DEGRADING ENZYME .2. PURIFICATION AND PROPERTIES OF SECONDARY ALCOHOL OXIDASE FROM A STRAIN OF PSEUDOMONAS

An enzyme which catalyzes the oxidation of poly(vinyl alcohol) has been purified to a homogeneous state from an enzyme preparation obtained from a culture broth of a strain of Pseudomonas and described previously as a poly(vinyl alcohol)-degrading enzyme (Y. Watanabe et al., Agric. Bioi. Chem., 39, 2447 (1975)). When the purified enzyme reacts on poly (vinyl alcohol), hydroxyl groups seem to be oxidized to keto groups and 1 mol of hydrogen peroxide is produced as I mol of molecular oxygen is consumed. Essentially no decrease is observed in the viscosity of poly(vinyl alcohol) solution. The enzyme is active not only to poly(vinyl alcohol) but also to a variety of low molecular weight secondary alcohols and 4heptanone is formed from 4-heptanol. A name of secondary alcohol oxidase has been proposed to the enzyme. The enzyme is a single polypeptide with a molecular weight of 50,000 with an isoelectric point at pH 10.3. Alanine and valine has been identified as N- and Cterminal residues, respectively. The enzyme is pink, has absorption maxima at 277, 364 and 466 nm, and contains 1 g atom of non-heme iron per molecule. No flavin has been detected. The enzyme is most active at pH 7 and at 50°C, and is stable between pH 4.5 and 9 and below 50°C. Among the compounds examined, Hg2+, Pb2+, Zn2+, o-phenanthroline and thylenediaminetetraacetate have shown weak inhibitions of the activity. The following two successive reactions, the first is catalyzed by the secondary alcohol oxidase and the second by a probable hydrolase have been postulated as a mechanism of bacterial degradation of poly (vinyl alcohol): © 1979 Taylor & Francis Group, LLC.