title: Adsorption between TC-stabilized AuNPs and the phosphate group: application of the PTP1B activity assay.
abstract: Based on the adsorption between tetracycline (TC) and phosphate groups, a general colorimetric method is explored in this work by using TC-stabilized gold nanoparticles (TC/AuNPs) and 4-aminophenyl phosphate-functionalized Fe3O4 magnetic nanoparticles (APP/MNPs). Taking protein tyrosine phosphatase 1B (PTP1B) as an example, 4-aminophenyl phosphate (APP) can be hydrolyzed into 4-aminophenol (AP) by PTP1B, resulting in the disappearance of the phosphate group on the outer layer of MNPs and the loss of corresponding adsorptive ability. Upon addition of TC/AuNP solution, TC/AuNPs will remain in the supernatant solution after magnetic separation and a high absorbance value can be observed. So PTP1B activity is related to the concentrations of TC/AuNPs in the supernatant solution. In this work, the enzyme activity can be determined at levels as low as 0.0885 U mL(-1) and over a linear detection range as wide as 0.1 U mL(-1) to 0.9 U mL(-1). Moreover, using the proposed method, the inhibition effect of betulinic acid (BA) and sodium orthovanadate (Na3VO4) on PTP1B activity can be tested with IC50 values of 30 μM and 4 μM, respectively. Therefore, a universal platform for the accurate colorimetric analysis of kinase and phosphatase activities can be established through the adsorption between TC and phosphate groups.
authors.affiliation: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, PR China. juanzhang@shu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Lv
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Wang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Defeng
authors.initials: D
authors.lastname: Li
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Lizhou
authors.initials: L
authors.lastname: Sun
mesh_terms: D000327:Adsorption; D001681:Biological Assay / Q000379:methods*; D003124:Colorimetry; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D015394:Molecular Structure; D010710:Phosphates / Q000737:chemistry*; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000032:analysis / Q000378:metabolism*; D013752:Tetracycline / Q000737:chemistry*
chemical_list: D004791:Enzyme Inhibitors; D010710:Phosphates; D006046:Gold; C516607:PTPN1 protein, human; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D013752:Tetracycline