Spectroscopic Studies On The Fraction Frequency Fluorescence Of HSA And On The Resonance Scattering Of DNA And HSA

Part l:At physiological pH ( 7.43 ) human serum albumin(HSA) and tryptophane(Trp) exhibit their fluorescence peaks at 344nm and 360nm,respectively, while their 1/2 fraction frequency fluorescence peaks at 688nm and 720nm. The ratio of half peak width and the ratio of peak height (or fluorescence intensity) between 1/2 fraction frequency fluorescence peak and the fluorescence peak approach a constant respectively. The two fluorescence peaks have similar fluorescence feature and their intensities weaken at the same time while strong absorbing substance in the wavelength of Trp (or HSA) fluorescence peak is added to; the two fluorescence peaks don't appear if the excitation wavelength is longer than that of fluorescence peak . According to the principle of nonlinear optics and fraction frequency, the relationship between half peak width and center wavelength (fluorescence peak wavelength) and the cause of fraction frequency fluorescence peak have been considered.Part II: At physiological pH(7.43),DNA exhibits the strongest and the second strong resonance scattering peaks at 470nm and 350nm,respectively. Rayleighx fraction frequency and double resonance frequency scattering peaks were found in the emission spectrum of DNA. Influence of pH?ionicstrength and surfactant on the intensity of light-scattering was studied. By this way, the variation of structure or conformation of DNA molecule has been inferred. According to the principle of quantum electrodynamics,the mechanism of all kinds of resonance scattering peaks caused by ordinary monochromatic light wasdiscussed systematically and the intensity of various resonance scattering light was also analysed.PartIII:Based on the formation of supramolecular ion-association complexes resulting from the combination of metal complex anions with proteins and the interface formation, a new method for the determination of human serum albumin (HSA) by using the technique of resonance scattering has been founded. In the medium of 2. 0 ICT'mol. dm'3 HC1, proteins may combine with [Fe(CN)6]3~ by intermolecular forces(mainly by electrostatic force) to supramolecular ion-association complexes, causing a light signal of the strongest resonance scattering at 351nm. Based on this, no less 0.3 lAg-ml"1 HSA can be determined . Its calibration curve is near over the range of Q-12\ig.mTl .The sensitivity of this method is three-fold higher than that of Coomassie brilliant blue protein assay. Influence of experimental conditions such as pH, ionic strength and concentration of [Fe(CN)6] * on the intensity of resonance scattering light was studied. Effects of surfactants (cationic, anionic and nonionic) > ami no acids and metal ions on the combination of [Fe(CN)6J3" with protein were also investigated .This method has been used for the determination of synthetic samples with satisfactory results .