木素生物降解酶活力的表面活性剂头基效应研究

用分光光度技术研究了木素生物降解关键酶木素过氧化物酶(LiP)和锰过氧化物酶(MnP)在不同类型表面活性剂存在下,催化氧化木素模型化合物藜芦醇(VA)、2,6-二甲氧基苯酚(DMP)和丁香醛连氮的活力.表面活性剂选择了非离子型、阴离子型和阳离子型中具有代表性的曲拉通-100(TX-100)、十二烷基硫酸钠(SDS)、琥珀酸二辛酯磺酸钠(AOT)、十六烷基三甲基溴化铵(CTAB).结果表明非离子型表面活性剂TX-100对MnP和LiP有激活作用,而离子型表面活性剂对两种酶均有抑制作用,且阴离子表面活性剂的抑制作用远大于阳离子表面活性剂.此外,就MnP而言,表面活性剂对酶促反应的影响大小还与底物性质有关.TX-100对高疏水性底物丁香醛连氮的激活作用要比低疏水性底物DMP大.

STUDY ON THE EFFECT OF SURFACTANT HEAD GROUP ON THE LIGNINOLYTIC ACTIVITY OF ENZYMES

The ligninolytic activity of lignin peroxidase (LiP) and Mn-dependent peroxidase (MnP) in the presence of different kinds of surfactants were determined by UV-vis spectrophotometric technique based on their catalytic effects on the oxidation of veratryl alcohol (VA),2,6-dimethoxyphenol (DMP) or syringaldazine.Four representative surfactants were selected.They were nonionic Triton X-100 (TX-100),anionic sodium dodecylsulfate (SDS),anionic sodium bis (2-ethylhexyl) sulfosuccinate (AOT),and cationic cetyltrimethylammonium bromide (CTAB).Results showed that nonionic TX-100 had an activating effect on both MnP and LiP,while the ionic surfactants had an inhibitory effect on them.The inhibitory effect of anionic surfactants was much stronger than that of cationic CTAB.Moreover,the effect of surfactants on the MnP catalyzed oxidation reaction depended on the properties of the substrates.The activating effect of TX-100 on more hydrophobic syringaldazine was stronger than that on less hydrophobic DMP.The results were of importance for selecting appropriate surfactant association system for biodegradation of lignin model compounds.