Yue-ming Hu,Su-zhen Lu,Ya-si Li,Hui Wang,Yan Shi,Lu Zhang,Zong-cai Tu
The protective effect of antioxidant peptides from grass carp scale gelatin on hydrogen peroxide (H 2 O 2 ) - mediated oxidative injured HepG2 cells was investigated, and the protective mechanism as well as peptide structure were studied. Pretreated with grass carp scale gelatin hydrolysates (GSGH) for 24 h significantly increased the survival rates and decreased the apoptosis rates of H 2 O 2 - mediated oxidative injured HepG2 cells. The increase in SOD, CAT and GPX activities, reduce in ROS level and MDA content, and weaken in damage on cell membrane and DNA could be responsible for the protective effect of GSGH on H 2 O 2 -mediated oxidative injured HepG2 cells. Peptide sequences of GSGH were analyzed by LC-ESI-Q-Orbitrap-MS/MS, and results showed that most of them were low molecular weight peptide at 358–986 Da. Synergistic effect existed among antioxidant peptides and contributed to the strong antioxidant activities of GSGH.
He Shao-Bin,Chen Feng-Qing,Xiu Ling-Fang,Peng Hua-Ping,Deng Hao-Hua,Liu Ai-Lin,Chen Wei,Hong Guo-Lin
Although a massive research has been devoted on the exploration of noble metal–based nanozyme, less progress has been made in the investigation of palladium (Pd) nanozyme and the interaction between ions and Pd nanozyme. In this study, a new type of Pd nanozyme was prepared by a facile one-pot approach by using carboxylated chitosan as the stabilizer. Owing to the synergistic effect of carboxylated chitosan stabilized Pd nanoparticles (CC-PdNPs) can effectively catalyze the H 2 O 2 -mediated oxidation of 3,3′,5,5′-tetramethylbenzidine sulfate (TMB) accompanied by a blue color change (oxidized TMB), indicating the peroxidase-like activity of CC-PdNPs. Furthermore, the Michaelis-Menten constants and catalytic stability of CC-PdNPs render them suitable for environmental analysis and bio-detection. Here, we found that while introducing the iodine ions (I − ) into the reaction medium, the peroxidase-like activity of CC-PdNPs has been rapidly and effectively inhibited through the formation of Pd-I bond; thus, the active sites of PdNPs can be blocked by I − . Based on this specific inhibition by I − , a facile colorimetric assay has been performed for the detection of I − with an extremely low limit of detection (0.19 nM). Furthermore, the practicality of the proposed sensor also has been demonstrated in tap water, and the satisfactory recoveries were obtained. Our study not only demonstrated a novel Pd–based nanozyme but also provided guidance for I − sensing for environmental analysis, food inspection, and bio-detection.
Graphical abstract
危险品化学品经营许可证（带存储）