The enzyme from Bacillus sp. OxB-1 contains protoheme IX, the iron of which must be in the form iron(II) for activity. (Z)-Phenylacetaldoxime binds to ferric heme (the iron(III) form) via the oxygen atom whereas it binds to the active ferrous form via the nitrogen atom. In this way, the oxidation state of the heme controls the coordination stucture of the substrate---heme complex, which regulates enzyme activity [2]. The enzyme is active towards several (Z)-arylacetaldoximes and (E/Z)-alkylaldoximes as well as towards arylalkylaldoximes such as 3-phenylpropionaldoxime and 4-phenylbutyraldoxime. However, it is inactive with phenylacetaldoximes that have a substituent group at an alpha-site of an oxime group, for example, with (E/Z)-2-phenylpropionaldoxime and (E/Z)-mandelaldoxime. The activity of the enzyme is inhibited completely by the heavy-metal cations Cu+, Cu2+, Ag+ and Hg+ whereas Fe2+ and Sn2+ have an activatory effect.
History
EC 4.8.1.4 created 2005 as EC 4.99.1.7, transferred 2021 to EC 4.8.1.4
Kato Y, Nakamura K, Sakiyama H, Mayhew SG, Asano Y
Title
Novel heme-containing lyase, phenylacetaldoxime dehydratase from Bacillus sp. strain OxB-1: purification, characterization, and molecular cloning of the gene.
