title: Probing the interaction of human serum albumin with DPPH in the absence and presence of the eight antioxidants.
abstract: Albumin represents a very abundant and important circulating antioxidant in plasma. DPPH radical is also called 2,2-diphenyl-1-picrylhydrazyl. It has been widely used for measuring the efficiency of antioxidants. In this paper, the ability of human serum albumin (HSA) to scavenge DPPH radical was investigated using UV-vis absorption spectra. The interaction between HSA and DPPH was investigated in the absence and presence of eight popular antioxidants using fluorescence spectroscopy. These results indicate the antioxidant activity of HSA against DPPH radical is similar to glutathione and the value of IC50 is 5.200×10(-5) mol L(-1). In addition, the fluorescence experiments indicate the quenching mechanism of HSA, by DPPH, is a static process. The quenching process of DPPH with HSA is easily affected by the eight antioxidants, however, they cannot change the quenching mechanism of DPPH with HSA. The binding of DPPH to HSA primarily takes place in subdomain IIA and exists two classes of binding sites with two different interaction behaviors. The decreased binding constants and the number of binding sites of DPPH with HSA by the introduction of the eight antioxidants may result from the competition of the eight antioxidants and DPPH binding to HSA. The binding of DPPH to HSA may induce the micro-environment of the lone Trp-214 from polar to slightly nonpolar.
authors.affiliation: Department of Chemistry, School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan 453003, PR China.
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, PR China.
authors.forename: Dejun
authors.initials: D
authors.lastname: Chen
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, PR China.
authors.forename: Gongke
authors.initials: G
authors.lastname: Wang
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, PR China. Electronic address: 1842457577@qq.com.
authors.forename: Yan
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry*; D006801:Humans; D010851:Picrates / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D010851:Picrates; D012709:Serum Albumin; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Antioxidants; DPPH; Fluorescence spectroscopy; Human serum albumin; UV–vis absorption spectroscopy