Parra C, Rodriguez J, Baeza J, Freer J, Durán N
Renewable Resources Laboratory, Universidad de Concepción, Chile.
Biochem Biophys Res Commun. 1998 Oct 20;251(2):399-402. doi: 10.1006/bbrc.1998.9315.
Iron-chelating low-molecular-weight compounds or catecholate siderophores have been suggested to be involved in wood biodegradation. To help in understanding the mechanism involved in the enzyme-like activity of catecholate siderophores, the oxidative properties of 2,3-dihydroxybenzoic acid (DHBA) and 3, 4-dihydroxyphenylacetic acid (DHPAA) chelated with iron were studied. The pH and catechol/Fe(III) ratios were optimized for o-dianisidine oxidation, obtaining a maximum at pH 7.0, in the absence of buffer, and a catechol/Fe(III) ratio of 1:2 to DHBA and 1:1 to DHPAA was found. Under these conditions, the catechols were able to reduce Fe(III) to Fe(II) acting like siderophore models. The Fe(III) complex of DHBA and of DHPAA degraded dioxane-lignin in 60% after 2 h and 85% after 24 h, respectively. DHBA/Fe(III) oxidized the bleaching effluent (E1) in 80% in 5 min under the studied conditions.
铁螯合低分子量化合物或儿茶酚型铁载体被认为参与木材生物降解。为了有助于理解儿茶酚型铁载体类酶活性所涉及的机制，研究了与铁螯合的2,3 - 二羟基苯甲酸（DHBA）和3,4 - 二羟基苯乙酸（DHPAA）的氧化特性。针对邻联茴香胺氧化对pH值和儿茶酚/铁（III）比例进行了优化，在无缓冲液的情况下，于pH 7.0时获得最大值，发现DHBA的儿茶酚/铁（III）比例为1:2，DHPAA的儿茶酚/铁（III）比例为1:1。在这些条件下，儿茶酚能够将铁（III）还原为铁（II），起到铁载体模型的作用。DHBA和DHPAA的铁（III）配合物分别在2小时后降解了60%的二氧六环 - 木质素，24小时后降解了85%。在所研究的条件下，DHBA/铁（III）在5分钟内将漂白废水（E1）氧化了80%。
