Department of Chemistry, Karamanoglu Mehmetbey University, 70100 Karaman, Turkey.
Int J Biol Macromol. 2013 May;56:34-40. doi: 10.1016/j.ijbiomac.2013.01.031. Epub 2013 Feb 8.
1-3,4-Dihydroxy phenylalanine called as l-Dopa is a precursor of dopamine and an important neural message transmitter and it has been a preferred drug for the treatment of Parkinson's disease. In this study, with regards to the synthesis of L-Dopa two types of biosensors were designed by immobilizing tyrosinase on conducting polymers: thiophene capped poly(ethyleneoxide)/polypyrrole (PEO-co-PPy) and 3-methylthienyl methacrylate-co-p-vinylbenzyloxy poly(ethyleneoxide)/polypyrrole (CP-co-PPy). PEO-co-PPy and CP-co-PPy were synthesized electrochemically and tyrosinase immobilized by entrapment during electropolymerization. L-Tyrosine was used as the substrate for L-Dopa synthesis. The kinetic parameters of the designed biosensors, maximum reaction rate of the enzyme (Vmax) and Michaelis Menten constant (Km) were determined. Vmax were found as 0.007 μmol/(minelectrode) for PEO-co-PPy matrix and 0.012 μmol/(minelectrode) for CP-co-PPy matrix. Km values were determined as 3.4 and 9.2 mM for PEO-co-PPy and CP-co-PPy matrices, respectively. Optimum temperature and pH, operational and shelf life stabilities of immobilized enzyme were also examined.
1-3,4-二羟基苯丙氨酸，即左旋多巴，是多巴胺的前体，也是一种重要的神经递质，它一直是治疗帕金森病的首选药物。在这项研究中，针对左旋多巴的合成，设计了两种基于固定化酪氨酸酶的生物传感器：噻吩封端的聚（氧化乙烯）/聚吡咯（PEO-co-PPy）和 3-甲基噻吩甲基丙烯酸酯-co-p-乙烯基苄氧基聚（氧化乙烯）/聚吡咯（CP-co-PPy）。PEO-co-PPy 和 CP-co-PPy 通过电化学合成，并在电聚合过程中通过包埋固定化酪氨酸酶。L-酪氨酸被用作合成 L-Dopa 的底物。设计的生物传感器的动力学参数，即酶的最大反应速率（Vmax）和米氏常数（Km）进行了测定。对于 PEO-co-PPy 基质，Vmax 为 0.007 μmol/（min·电极），对于 CP-co-PPy 基质，Vmax 为 0.012 μmol/（min·电极）。对于 PEO-co-PPy 和 CP-co-PPy 基质，Km 值分别确定为 3.4 和 9.2 mM。还研究了固定化酶的最佳温度和 pH 值、操作和货架寿命稳定性。
