非离子表面活性剂存在下过氧化氢对木素过氧化物酶的抑制动力学研究

Kinetic Studies on The Inhibition of Ligninase By Hydrogen Peroxide in the Presence of Nonionic Surfactant

研究表面活性剂水溶液体系中木素模型化合物的酶法降解机制具有重要意义 .本文用动力光度技术研究了非离子表面活性剂TritonX 10 0 (TNX)存在下过氧化氢对木素过氧化物酶 (LiP)的抑制作用 .结果表明 ,该抑制作用属可逆竞争抑制 .TNX的存在使H2 O2 的抑制作用加强 ,抑制常数Ki值下降 .Ki值随TNX浓度 (远低于、接近于和远大于其临界胶束浓度 )变化很小这一结果表明起主导作用的是TNX单体 。

Studies of biodegradation of lignin model compounds by enzyme in aqueous media containing surfactant is of great significance to the world's environment and resources. In this paper, the inhibition of ligninase (LiP) by hydrogen peroxide in the presence of nonionic surfactant TritonX 100 has been investigated using kinetic spectrophotometric technique. Based on the results of kinetic studies of the ligninase catalyzed oxidation of veratryl alcohol (VA) by H 2O 2 , a reversible competitive pattern of inhibition is suggested. Presence of TritonX 100 enhances the inhibition by H 2O 2 and, therefore, causes the inhibition constant Ki to decrease. Based on the fact that Ki changes little with the concentrations of TritonX 100 (lower than, near to, and larger than its critical micelle concentration), it may be concluded that the monomer of TritonX 100, maybe through its modification to the enzymic protein, is responsible for the above mentioned results.