title: A simple and visible colorimetric method through Zr(4+)-phosphate coordination for the assay of protein tyrosine phosphatase 1B and screening of its inhibitors.
abstract: Inhibitors of protein tyrosine phosphatase 1B (PTP1B) are promising agents for the treatment of type 2 diabetes and obesity, so a colorimetric method has been developed in this work for PTP1B assay and screening of its inhibitors. The method is based on the chelation effect of zirconium (Zr(4+)) ions on the phosphate group, which may induce aggregation of 4-aminophenylphosphate-functionalized gold nanoparticles (APP/AuNPs) and the corresponding color change of the testing solution. Owing to the dephosphorylation of PTP1B, the aggregation of AuNPs will be influenced by PTP1B since there is no coordination reactivity between Zr(4+) ions and 4-aminophenol, the hydrolyzed product of APP catalyzed by the enzyme. Therefore, a simple colorimetric method for the assay of PTP1B activity can be developed. Under the optimized experimental conditions, the ratios of absorbance at a wavelength of 650 nm to that at 522 nm vary linearly with the PTP1B activity in the range from 0.005 to 0.18 U mL(-1) with the lowest detection limit of 0.0017 U mL(-1). Moreover, using this proposed method, the inhibition effect of 6-chloro-3-formyl-7-methylchromone, betulinic acid, ursolic acid, and sodium orthovanadate on PTP1B activity can be tested with IC50 values of 10, 13, 9, and 1.1 μM, respectively. Therefore, this new method has great potential not only for the detection of PTP1B activity but also for the screening of the inhibitors.
authors.affiliation: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China. genxili@nju.edu.cn.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Lv
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Wang
authors.forename: Defeng
authors.initials: D
authors.lastname: Li
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Wang
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D003124:Colorimetry; D056831:Coordination Complexes / Q000737:chemistry*; D004353:Drug Evaluation, Preclinical; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D004791:Enzyme Inhibitors; D015040:Zirconium; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1