Aldehyde oxidase carrying an unusual subunit structure from Pseudomonas sp. MX-058

Abstract

Pseudomonas sp. MX-058 produces aldehyde oxidase catalysing glyoxal to glyoxylic acid. Two aldehyde oxidases (F10 and F13) were purified to homogeneity from Pseudomonas sp. MX-058. F10 and F13 had subunit structures, a heterotetramer and heteropentamer respectively. The N-terminal amino acid sequences of all subunits were highly homologous to amino acid sequences of the putative oxidoreductases of Pseudomonas strains. All of these homologous oxidoreductases have a heterotrimer structure consisting of 85-88 (α), 37-39 (β) and 18-23 (γ) kDa subunits. However, the α-subunits of F10 and F13 might have decomposed into two [80 (α1) and 9 kDa (α2)] and three [58 (α1′), 22 (α1″) and 9 (α2) kDa] subunits, respectively, while the β- and γ-subunits remained intact. Both F10 and F13 show high activity toward several aliphatic and aromatic aldehydes. The aldehyde oxidases of Pseudomonas sp. MX-058 has unique protein structures, α1α2βγ for F10 and α1′α1″α 2βγ for F13, a heterotetramer and heteropentamer respectively. The enzymes exhibit significantly low activity toward glyoxylic acid compared with glyoxal, which is an advantageous property for glyoxylic acid production from glyoxal. © 2008 The Authors.