title: [Study and application of determination of protein with meso-tetra-(3,5-dibromo-4-hydroxyphenyl) porphyrin fading spectrophotometry].
abstract: In the present paper, the binding characteristics and spectral behavior of interaction of meso-tetra-(3, 5-dibromo-4-hydroxyphenyl) porphyrin [T(DBHP)P] as a new-style probe with protein were studied by the techniques of spectrophotometry. The experiment showed that Tween-80 microemulsion was efficiently used to enhance the sensibility and stability of the system at pH 4. 17(Britton-Robinson buffer solution). Under optimum conditions, the characteristics of absorption spectral of meso-tetra-(3,5-dibromo-4-hydroxyphenyl) porphyrin-protein were investigated, the maximum absorption was located at 425 nm, and the reducing value of absorbance A was in proportion to the concentration of proteins in the range 0.50-6.00 microg x mL(-1) for bovine serum albumin, 0.05-0.60 microg x mL(-1) for ovalbumin, and the limits of detection were 0.106 microg x mL(-1) for bovine serum albumin and 0.039 microg x mL(-1) for ovalbumin. The experiments indicated that the proposed method featured high sensitivity and good selectivity and stability, and was simple and relatively free from interference of coexistent substances. It has been applied to the determination of protein in milk samples with satisfactory. The recovery for the investigated protein from milk was 99.56%-100.2% and the relative standard deviations were less than 2.2%. The sensitive method for the quantitative determination of proteins was proposed and may be applicable to the determination of ultra amounts of protein in food analysis. The effect of ionic strength on the system was investigated, and the result indicated that the binding force between meso-tetra-(3, 5-dibromo-4-hydroxyphenyl) porphyrin and protein was judged as electrostatic force. The influence of protein denaturation was also studied, under higher temperature the structure of protein was destroyed, and thermodynamic movement of the molecular of protein was intensified as the heating time extended.
authors: School of Chemistry and Chemical Engineering, University of Ji'nan, Ji'nan 250022, China.
authors: Mei
authors: M
authors: Yan
authors: Xin
authors: X
authors: Chen
authors: Li-Na
authors: LN
authors: Zhang
authors: Hong-Min
authors: HM
authors: Ma
authors: Shu-Ting
authors: ST
authors: Sun
authors: Qin
authors: Q
authors: Wei
mesh_terms: D000818:Animals; D002417:Cattle; D008892:Milk / Q000737:chemistry; D011166:Porphyrins / Q000737:chemistry; D011506:Proteins / Q000032:analysis*; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods*; D013816:Thermodynamics
chemical_list: D011166:Porphyrins; D011506:Proteins