铽-G-四链体-血红素复合物的过氧化物氧化酶活性及其硫化氢比色检测

It is of great importance to simply and sensitively detect hydrogen sulfide (H2S) because of its role in various physiological processes as well as its inherent toxicity. In this work, a colorimetric method for H2S detection was developed by employing terbium-G-quadruplex-hemin (Tb/G4-hemin) DNAzyme a peroxidase mimic, which can catalyze the H2O2-mediated oxidation of 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) to produce radical cation (ABTSo+). In the presence of Ag+, the peroxidase-like activityof Tb/G4-hemin DNAzyme can be inhibited significantly owing to the disruption of G-quadruplex structure. However, the addition of H2S can effectively suppress such negative behavior by competitive binding with Ag+, leading to the recovery of the peroxidase-like activity of Tb/G4-hemin DNAzyme, which can be reflected by an increase in absorbance signal of ABTSo+. The absorbance of ABTSo+ was enhanced linearly with increasing the H2S concentration from 20 nM to 2 μM. The detection limit for H2S is 13 nM, which is much lower than most of previous methods. Moreover, the proposed method possesses the features of simple preparation, easy reproducibility and good biocompatibility.