Molecular and Catalytic Properties of 2,4′-Dihydroxyacetophenone Dioxygenase from Burkholderia sp AZ11
Molecular and Catalytic Properties of 2,4′-Dihydroxyacetophenone Dioxygenase from Burkholderia sp AZ11
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DOI：
10.1271/bbb.110867
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发表时间：
2012-03-01
影响因子：
1.6
通讯作者：
Maruyama, Kiyofumi
中科院分区：
文献类型：
--
作者：
Enya, Mayu;Aoyagi, Keiko;Maruyama, Kiyofumi
The gene dad encoding 2,4'-dihydroxyacetophenone (DHAP) dioxygenase was cloned from Burkholderia sp. AZ11. The initiation codon GTG was converted to ATG for high-level expression of the enzyme in Escherichia coli. The enzyme was moderately thermostable, and the recombinant enzyme was briefly purified. The enzyme (M-r = 90 kDa) was a homotetramer with a subunit Mr of 23 kDa. It contained 1.69 mol of non-heme iron, and had a dark gray color. On anaerobic incubation of it with DHAP, the absorption at around 400 nm increased due to the formation of an enzyme-DHAP complex. Multiple sequence alignment suggested that His77, His79, His115, and Glu96 in the cupin fold were possible metal ligands. The apparent K-m for DHAP and the apparent V-max were estimated to be 1.60 mu m and 6.28 mu mol/min/mg respectively. 2-Hydroxyacetophenone was a poor substrate. CuCl2 and HgCl2 strongly inhibited the enzyme, while FeSO4 weakly activated it.
