title: Selective and sensitive homogenous assay of serum albumin with 1-anilinonaphthalene-8-sulphonate as a biosensor.
abstract: Homogenous selective assay of albumin (ALB) in clinical sera was tested with 1-anilinonaphthalene-8-sulphonate (ANS) as Förster-resonance-energy-transfer (FRET) acceptor of tryptophan residues and biosensor of ALB. Between the excitation at 280 and 350 nm, the ratio of the fluorescence at 470 nm of free ANS in ethanol was about 1.9 while that of the complexes of ALB and ANS was about 3.9, supporting FRET in complexes of ANS and ALB. ANS below 1.0 mM saturated one site of ALB with Kd of about 0.13 μM in 20 mM sodium phosphate buffer at pH 7.0. For selective assay of ALB, 0.30 μM ANS was used to quantify fluorescence of the complexes at 470 nm under the excitation at 280 nm. ALB from 1.8 to 25 nM was quantified, whose lower limit was below 1% than that by bromocresol green assay while one-third than that by immunoturbidimetric assay. Globular proteins at comparable levels gave negligible signals. This new method showed reasonable resistance to other interfering substances in clinical sera. Quantities of ALB in clinical sera by this method were consistent with those by bromocresol green assay and immunoturbidimetric assay. Hence, homogenous assay of ALB with ANS as FRET biosensor was effective.
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Jialin
authors.initials: J
authors.lastname: Qin
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Yuanli
authors.initials: Y
authors.lastname: Li
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Chenxiong
authors.initials: C
authors.lastname: He
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Hu
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Chen
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Pu
authors.affiliation: Unit for Analytical Probes and Protein Biotechnology, Key Laboratory of Clinical Laboratory Diagnostics of the Education Ministry, College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China. Electronic address: liaofeish@yahoo.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Liao
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry*; D015374:Biosensing Techniques; D031541:Fluorescence Resonance Energy Transfer; D005470:Fluorometry; D006801:Humans; D012709:Serum Albumin / Q000032:analysis / Q000737:chemistry*
chemical_list: C515594:8-anilino-1-naphthalenesulfonic acid; D000817:Anilino Naphthalenesulfonates; D012709:Serum Albumin
keywords: 1-Anilinonaphthalene-8-sulphonate; Förster-resonance-energy-transfer; Homogenous noncompetitive assay; Serum albumin