Enzymatic Spectrophotometric Method for Aflatoxin B Detection Based on Acetylcholinesterase Inhibition
作者:Fabiana Arduini、Ilenia Errico、Aziz Amine、Laura Micheli、Giuseppe Palleschi、Danila Moscone
DOI:10.1021/ac061819j
日期:2007.5.1
A new method for aflatoxin B (AFB) determination is proposed. The AFB determination is based on acetylcholinesterase (AChE) inhibition, and the AChE residual activity is determined using the colorimetric method (Ellman's method). Cholinesterases (ChEs) from various sources were tested using AFB1 as reference aflatoxin. AChE from electric eel has shown the highest sensitivity to AFB1, and it was chosen for the rest of the work. To select and optimize the analytical procedures, an investigation on the type of AChE inhibition by AFB1 was carried out. The AChE degree of inhibition by AFB1 was independent of the incubation time and the enzyme concentrations, showing the reversibility of the inhibition. This reversibility of the inhibition permits a rapid analysis of AFB1, requiring only 3 min. For the development of the AFB1 assay, the pH, the time of reaction, temperature, and substrate concentration were evaluated and optimized. The linear range of 10−60 ng mL-1 was determined. To evaluate the selectivity of this method, the cross-reactivity with other aflatoxins such as aflatoxin B2, aflatoxin G1, aflatoxin G2, and aflatoxin M1 was investigated. Finally, the suitability of the assay for AFB1 quantification in barley was evaluated. This study shows a new approach to detect aflatoxins based on enzyme inhibition and has advantages such as the ease of use, rapidity, and cost effectiveness. Thus, it could find a possible use as a screening method for this type of mycotoxins.
本文提出了一种测定黄曲霉毒素 B(AFB)的新方法。AFB 的测定以乙酰胆碱酯酶(AChE)抑制作用为基础,用比色法(埃尔曼法)测定乙酰胆碱酯酶的残余活性。以 AFB1 作为参考黄曲霉毒素,对不同来源的胆碱酯酶(ChEs)进行了测试。电鳗中的乙酰胆碱酯酶对 AFB1 的敏感性最高,因此被选为后续研究的对象。为了选择和优化分析程序,对 AFB1 对 AChE 的抑制类型进行了调查。AFB1 对 AChE 的抑制程度与孵育时间和酶浓度无关,这表明抑制作用具有可逆性。这种抑制的可逆性使 AFB1 的快速分析成为可能,只需 3 分钟。为开发 AFB1 检测方法,对 pH 值、反应时间、温度和底物浓度进行了评估和优化。该方法的线性范围为 10-60 毫微克/毫升。为了评估该方法的选择性,研究了与其他黄曲霉毒素(如黄曲霉毒素 B2、黄曲霉毒素 G1、黄曲霉毒素 G2 和黄曲霉毒素 M1)的交叉反应。最后,还评估了该检测方法对大麦中 AFB1 定量的适用性。这项研究展示了一种基于酶抑制作用检测黄曲霉毒素的新方法,具有使用方便、快速和成本效益高等优点。因此,该方法可用作这类霉菌毒素的筛选方法。