DNA吸附消除黄曲霉毒素G1

Removal of Aflatoxin G1 by DNA Adsorption

摘要:

鉴于黄曲霉毒素G1（AFG1）的毒性强，难降解和有效去除，利用AFG1与DNA的嵌插结合，构建选择性吸附消除AFG1的有效方法。AFG1嵌入DNA的最佳反应条件为pH 7.4及30 ℃，其DNA结合饱和值和去除率为1.66、88.14%。添加NaCl、CaCl2、L-天冬氨酸、葡萄糖、尿素、亮氨酸、赖氨酸、维生素C等后，DNA结合饱和值分别为1.45、1.45、1.29、1.05、1.95、1.95、2.32和2.90。去除率分别为78.08%、76.44%、75.92%、75.16%、88.41%、88.67%、88.87%、90.27%。NaCl、CaCl2、L-天冬氨酸、葡萄糖等负电基团或者离子强度较高不利于AFG1-DNA嵌插结合，而尿素、亮氨酸、赖氨酸、维生素C等带正电基团和相似基团的物质利于AFG1-DNA的嵌插结合。花生油中的AFG1的去除率达到80%以上。动力学相关系数和吸附容量可知，该吸附过程符合准二级动力学模型，表明吸附过程的限速步骤为化学相互作用。吸附过程遵循Freundlich等温吸附模型，该吸附过程为多层吸附。热力学结果显示DNA对AFG1的吸附是自发的放热过程。综上，DNA能选择性吸附AFG1，因此，可进一步开发DNA新型材料，在去除食品中黄曲霉毒素方面有重要意义。

Abstract:

In view of the high toxicity of aflatoxin G1 (AFG1) and the difficulty in decomposing and effectively removing it, an effective method for selective adsorption and elimination of AFG1 was established via intercalation of AFG1 and DNA. The optimum reaction conditions for intercalating AFG1 into DNA molecules were pH 7.4 and 30 ℃, and the DNA binding saturation value and removal rate were 1.66 and 88.14%. After the addition of sodium chloride, calcium chloride, L-aspartic acid, glucose, urea, leucine, lysine or vitamin C, the DNA binding saturation values were 1.45, 1.45, 1.29, 1.05, 1.95, 1.95, 2.32 and 2.90 respectively, with the removal rates being 78.08%, 76.44%, 75.92%, 75.16%, 88.41%, 88.67%, 88.87% and 90.27% respectively. A negatively charged group (such as sodium chloride, calcium chloride, L-aspartic acid and glucose), or a relatively high ionic strength, was not conducive to the intercalation of AFG1 and DNA, whilst substances carrying positively charged groups and similar groups (such as urea, leucine, lysine, and vitamin C) were conducive to the AFG1-DNA intercalation. The removal rate of AFG1 in peanut oil reached over 80%. The kinetic correlation coefficient and adsorption capacity showed that the adsorption process conformed to the pseudo-second-order order model, indicating that the rate-limiting step of the adsorption process was chemical interaction. The adsorption process followed the Freundlich isotherm adsorption model, thus the adsorption process was multilayer adsorption. Thermodynamic results showed that the adsorption of AFG1 by DNA was a spontaneous exothermic process. In conclusion, DNA can selectively adsorb AFG1. Therefore, new DNA materials can be further developed, which is of great significance in the removal of aflatoxin in food.