Production of a Natural Dihydropteroate Synthase and Development of a Signal-Amplified Pseudo-Immunoassay for the Determination of Sulfonamides in Pork

Abstract

In this study, a type of magnetic photoaffinity-labeled activity-based protein profiling probe for sulfonamide drugs was first synthesized for the purpose of capturing the natural dihydropteroate synthase of Escherichia coli by using simple incubation and magnetic separation. After characterization of its identity with LC-ESI-MS/MS, this enzyme was used as a recognition reagent to develop a direct competitive pseudo-ELISA for the determination of the residues of 40 sulfonamides in pork. Because of the use of streptavidin-horseradish peroxidase and biotinylated horseradish peroxidase as a signal-amplified system, the limits of detection for the 40 drugs were in the range of 0.001–0.016 ng/mL. Compared to the steps in a conventional assay formation, the operation steps were the same, but the sensitivities increased 32–88-fold. Furthermore, the assay performances were better than the previously reported immunoassays performances for sulfonamides. Therefore, this method could be used as a practical tool for multiscreening the trace levels of sulfonamides residues in food samples.

Identification and Evolution of a Natural Tetr Protein Based on Molecular Docking and Development of a Fluorescence Polari-Zation Assay for Multi-Detection of 10 Tetracyclines in Milk

“…The identity of our recently obtained natural TetR was identified by using the LC-ESI-MS/MS technique, and the procedures were according to our recent report [ 37 ]. After this experiment, its gene sequence and amino acid sequence were obtained from NCBI.…”

Development of a receptor based signal amplified fluorescence polarization assay for multi-detection of 35 sulfonamides in pork

“…So, DHPS is the receptor of SAs that should recognize all SAs species. By now, there have been several DHPS-based pseudo-ELISA methods ( He et al, 2022 , Liang et al, 2020 , Liang et al, 2019 , Liang et al, 2013 ) and fluorescence polarization assays ( He et al, 2022 , Wang et al, 2015 ) reported for the detection of SAs residues. Among these analytical methods, fluorescence polarization assay is the simplest, rapidest, and most suitable tool for high-throughput analysis of large-scale samples because it does not require the conventional blocking, incubating, and washing steps.…”

Flexible and Transparent SERS Substrates Composed of Au@Ag Nanorod Arrays for In Situ Detection of Pesticide Residues on Fruit and Vegetables

“…One of the important measures is to detect pesticide residues in agricultural products sensitively and instantly. Presently, the typical detection approaches to pesticide residues include, but are not limited to, high-performance liquid chromatography (HPLC) [3], gas chromatographymass spectrometry (GC-MS) [4], and enzyme inhibition methods [5]. However, these methods generally require complex operation, large volume of samples, and a long time for measurement, so they cannot be applied to on-site food inspection [6].…”