Nguyen Le Truc, Ho Wing Fat, Yang Kun-Lin
Department of Chemical and Biomolecular Engineering, National University of Singapore 4 Engineering Drive 4 Singapore 117585
RSC Adv. 2020 May 5;10(30):17408-17415. doi: 10.1039/d0ra02472d.
Peroxidases are enzymes that use hydrogen peroxide to oxidize substrates such as 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ATBS). In this study, we showed that copper-tripeptide complexes ("cuzymes") also exhibited peroxidase-like activities. Different cuzymes could be formed by using various tripeptide ligands, such as GGG, GGH or HGG. However, the peroxidase-like activity of cuzymes depends on the sequence of the tripeptide (Cu-GGG > Cu-HGG > Cu-GGH). When ABTS was used as the substrate, the activity of Cu-GGG was 326 ± 1.5 U mg which was 2.5 times higher than that of horseradish peroxidase (HRP). Copper-tripeptide complexes were also used to degrade trypan blue dye. By using 0.2 mM Cu-GGG and 0.2% HO, 200 μM trypan blue could be degraded in 15 min at 50 °C. The degradation reaction followed second-order kinetics; the reaction rate was proportional to both HO concentration and the copper-tripeptide concentration, but it was independent of the trypan blue concentration. Because copper-tripeptides catalyzed the oxidation reactions involving HO effectively, they may have potential applications in biochemical assays and environmental remediation.
过氧化物酶是一类利用过氧化氢氧化诸如2,2-联氮-双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)等底物的酶。在本研究中，我们表明铜三肽复合物(“铜酶”)也表现出类似过氧化物酶的活性。通过使用各种三肽配体，如GGG、GGH或HGG，可以形成不同的铜酶。然而，铜酶的类似过氧化物酶活性取决于三肽的序列(Cu-GGG > Cu-HGG > Cu-GGH)。当使用ABTS作为底物时，Cu-GGG的活性为326±1.5 U mg，比辣根过氧化物酶(HRP)高2.5倍。铜三肽复合物也被用于降解台盼蓝染料。在50℃下，使用0.2 mM Cu-GGG和0.2% H₂O₂，200 μM台盼蓝可在15分钟内被降解。降解反应遵循二级动力学；反应速率与H₂O₂浓度和铜三肽浓度均成正比，但与台盼蓝浓度无关。由于铜三肽能有效催化涉及H₂O₂的氧化反应，它们在生化分析和环境修复中可能具有潜在应用。
