α-amanitin is the most toxic amanita in mushrooms with lethal dose to humans around 0.1 mg. Kg −1 . Hence, early identification of the poison would improve survival rates and prevent lethal poisoning cases. In this study, molecularly imprinted photonic crystal (MIPC) sensor was prepared by combining molecular imprinting with photonic crystal templates and tested towards the detection of α-amanitin. In this process, synthesized moiety of α–amanitin was utilized as template, dispersed SiO 2 colloidal photonic crystal as carrier, methacrylic acid (MAA) as functional monomer , and ethylene glycol dimethacrylate (EDGMA) as crosslinker. The adsorption behavior of MIPC towards α-amanitin in ethanol solution showed shifts in diffraction peaks of MIPC upon binding with α-amanitin molecules. The reflection peak wavelength varied linearly with α-amanitin concentration according to the correlation formula: λ = 15.417 c +489.17 (R 2 = 0.9985). The recognition process was accompanied by gradual color change in MIPC film. The prepared MIPC sensor possessed wide linear range (10 −9 –10 −3 mg L −1 ), change in visual color, low detection limit (10 −10 mg L −1 ), short response time (2 min), and good reusability. The MIPC film was then tested towards the detection of α-amanitin in real biological samples (mushroom, urine, and serum) and showed reasonable shift in diffraction peaks and color change upon soaking in solutions spiked with α-amanitin at 10 −6 mg L −1 and 10 −3 mg L −1 , suggesting the suitability of the film for the rapid identification of α-amanitin in complex sample matrices. Overall, the proposed sensor looks promising for the rapid identification of α-amanitin in clinical analysis and food poisoning.
Qici Wu,Qilei Zhang,Shiwen Xu,Chengtong Ge,Shanjing Yao,Dongqiang Lin
Five tryptophan analogues with a hydrophobic indole ring and an amino group on each molecule were used as functional ligands of mixed-mode resins for human serum albumin (HSA) purification. Their adsorption performance was evaluated and the effects of pH and salt addition on HSA adsorption were studied. The resins prepared showed typical pH-dependent adsorption and the highest adsorption capacity and affinity were found at pH 5.0 for all the resins tested. The saturated adsorption capacity was 138.02 mg·g − 1 with the tryptamine-functionalized resin, which significantly decreased at pH below 4.0 due to electrostatic repulsion between ligands and HSA. Moreover, the addition of NaCl or (NH 4 ) 2 SO 4 in media reduced HSA adsorption capacity, although the two salts showed different affecting profiles. The tryptamine-functionalized resin showed the best salt-tolerant performance, and its high adsorption capacity was maintained under high salt concentrations. In addition, the five resins prepared showed good adsorption selectivity for recombinant HSA from Pichia pastoris broth. Molecular docking results between tryptamine and HSA indicated that tryptamine was favorable to bind on Site II (indole-binding site) of HSA.
Yuting Li,Xiaotong Li,Jinshun Ye,Zhenzhao Weng,Xiaozhen Liu,Fengyuan Liu,Jingkun Yan,Lin Li
The reactivity of amino acid residues in proteins towards quinones, along with the concentration of quinones, may play a crucial role in determining the specific sites of reaction between quinones and proteins. The reaction efficiencies of 20 different α-carbon amine group blocked amino acids with 4-methylbenzoquinone (4MBQ) were investigated at pH 7.0 by cyclic voltammetry. Among these, Nα-acetyl- l -lysine, Nα-Boc- l -histidine, Nα-acetyl- l -arginine, and Nα-acetyl- l -cysteine exhibited reactivity towards 4MBQ, with the reactivity sequence being: Nα-acetyl- l -cysteine > Nα-acetyl- l -lysine > Nα-acetyl- l -arginine > Nα-Boc- l -histidine. In addition, the reactivity of Nα-acetyl- l -cysteine towards 4MBQ was over 50-fold greater than that of Nα-acetyl- l -lysine, Nα-Boc- l -histidine and Nα-acetyl- l -arginine. Adducts formed from the reaction of 4MBQ with Nα-acetyl- l -lysine and Nα-acetyl- l -arginine were identified as quinone adducts. In contrast, those formed with Nα-acetyl- l -cysteine and Nα-Boc- l -histidine were identified as phenol adducts through UPLC-QTOF-MS/MS analysis. Irrespective of whether the molar ratio of 4MBQ to protein free thiol groups was 1:2 or 2:1, the residues of cysteine, lysine, arginine and histidine in β-lactoglobulin (β-Lg) invariably engaged in the reaction with 4MBQ. This work may provide valuable information for design polyphenol-protein covalent conjugates which can be further applied as functional additives in food industry by choosing protein with different proportion of lysine, histidine, arginine and cysteine residues.
危险品化学品经营许可证（带存储）