The relations between oxidase activity on aldehyde alcohols and superoxide dismutase (SOD) were investigated, since the amino terminal amino acid sequence of alcohol oxidase (AOD) from Paenibacillus sp. AIU 311, which was specific to aldehyde alcohols, exhibited high similarity to those of SODs containing manganese (Mn(2+)-SOD). Paenibacillus AOD had high SOD activity. The SODs containing manganese, iron, or copper and zinc also exhibited oxidase activities on aldehyde alcohols, and the relative values of oxidase activities on aldehyde alcohols to SOD activity of Mn(2+)-SOD were closer to those of Paenibacillus AOD compared with those of the other SODs. Thus, SODs had AOD activity on aldehyde alcohols as another enzyme activity, and the Paenibacillus AOD and Mn(2+)-SOD were classified into a similar group.

An alcohol oxidase (AOD) was found from Aspergillus ochraceus AIU 031, and its characteristics were revealed. This enzyme oxidized short-chain primary alcohols and ethylene glycol, and belonged to the same group as AOD from methylotrophic yeast. However, it differed in the following properties. The K(m) value for ethanol was larger and that for ethylene glycol was smaller than those of AODs derived from methylotrophic yeasts. The ethanol oxidation was optimal at pH 5-7 and 50-55 degrees C. The molecular mass of this enzyme was 262 kDa and consisted of four identical subunits of 68 kDa, which were much smaller than those of methylotrophic yeasts.

An oxidase catalyzing the conversion of glycolaldehyde to glyoxal was purified to the homogeneous state from Paenibacillus sp. AIU 311, and its properties were revealed. This enzyme was specific to glycolaldehyde and glyceraldehyde, and the reaction rates to other alcohols and aldehydes were less than 6% of that of glycolaldehyde. The Km values for glycolaldehyde and glyceraldehyde were estimated to be 13.2 and 7.5 mM, respectively. The glycolaldehyde oxidation was optimum at pH 6.5 and 50 degrees C. The molecular mass of this enzyme was 49 kDa, and it consisted of two identical subunits of 24 kDa. The NH2-terminal sequence was not homologous to those of alcohol oxidases. This is the first report of an oxidase exhibiting high specificity to a hydroxy group of aldehyde alcohols.