Preparation and characterization of the hapten-protein conjugates are fundamental to developing environmental immunoassays. As a hapten, 1-pyrenebutyric acid（PBA） was conjugated to the carrier protein of bovine seru...Preparation and characterization of the hapten-protein conjugates are fundamental to developing environmental immunoassays. As a hapten, 1-pyrenebutyric acid（PBA） was conjugated to the carrier protein of bovine serum albumin（BSA） or ovalbumin（OVA） by active ester method. Infrared spectra（IR） showed that PBA-BSA and PBA-OVA conjugates were successfully prepared. The number of the haptens conjugated to the carrier protein was determined by ultraviolet spectra（UV） and matrix-assisted laser desorption ionization time-of-flight mass spectrometry（MALDI-TOF-MS）. The calculated average binding ratios of PBA/BSA and PBA/OVA were 18：1 and 10：1 by UV, and 31：1 and 22：1 by MALDI-TOF-MS, respectively. Although there was a discrepancy between the results determined by the two methods, both of them were useful for the characterization of the hapten-protein conjugates. The antibody was produced against the antigen of PBA-BSA, and the affinity was tested by the double agar diffusion method The conjugates and the antibody could be used for developing a sensitive and selective immunoassay of polycyclic aromatic hydrocarbons（PAHs）.展开更多
The binding constant（KDOM） of pyrene onto different molecular weight（Mw） fractions of a dissolved organic matter（DOM） extract from an estuarine sediment was measured via a fluorescence quenching method,and the p...The binding constant（KDOM） of pyrene onto different molecular weight（Mw） fractions of a dissolved organic matter（DOM） extract from an estuarine sediment was measured via a fluorescence quenching method,and the possible binding mechanisms were discussed.The influence of water chemical parameters on pyrene binding was studied to elucidate the effects of DOM steric conformation.DOM fraction with larger M w（14000） showed a greater KDOM（2.02×10 5） than that with smaller Mw did,and the KDOMs were 1.16×105 and 1.13×105 for the fractions with M w of 1000―14000 and 1000,respectively.The K DOM s of different M w DOM fractions were correlated positively with the atomic ratio of C/H and absorbance at 280 nm;while a negative correlation existed between K DOM and（O＋C）/N（atomic ratio）,and K DOM and O-containing groups.These correlations indicate the positive influence of aromatic structure and the negative effect of polarity on DOM binding capacity.Infrared spectroscopy revealed that specific interactions existed between pyrene and the DOM fraction with larger M W besides hydrophobic partition,i.e.,NH-π interaction in DOM moiety（1000―14000） and π-π electron donor acceptor（EDA） forces in DOM moiety（14000）.KDOM varied in a complex pattern with increasing cation concentration and pH,which could be explained by the change in DOM steric conformation.Formed aggregates favored the lipophilic partition of pyrene.However,the accessibility to some interior binding sites became low when the aggregate was too large,leading to a reduced KDOM.展开更多
基金Supported by National High-Tech Research and Development Program of China(No.2002AA649180)PhD Programs Foundation of Ministry of Education of China(No.20010055005)
文摘Preparation and characterization of the hapten-protein conjugates are fundamental to developing environmental immunoassays. As a hapten, 1-pyrenebutyric acid（PBA） was conjugated to the carrier protein of bovine serum albumin（BSA） or ovalbumin（OVA） by active ester method. Infrared spectra（IR） showed that PBA-BSA and PBA-OVA conjugates were successfully prepared. The number of the haptens conjugated to the carrier protein was determined by ultraviolet spectra（UV） and matrix-assisted laser desorption ionization time-of-flight mass spectrometry（MALDI-TOF-MS）. The calculated average binding ratios of PBA/BSA and PBA/OVA were 18：1 and 10：1 by UV, and 31：1 and 22：1 by MALDI-TOF-MS, respectively. Although there was a discrepancy between the results determined by the two methods, both of them were useful for the characterization of the hapten-protein conjugates. The antibody was produced against the antigen of PBA-BSA, and the affinity was tested by the double agar diffusion method The conjugates and the antibody could be used for developing a sensitive and selective immunoassay of polycyclic aromatic hydrocarbons（PAHs）.
基金Supported by the National Natural Science Foundation of China(Nos.20737002,41073087)
文摘The binding constant（KDOM） of pyrene onto different molecular weight（Mw） fractions of a dissolved organic matter（DOM） extract from an estuarine sediment was measured via a fluorescence quenching method,and the possible binding mechanisms were discussed.The influence of water chemical parameters on pyrene binding was studied to elucidate the effects of DOM steric conformation.DOM fraction with larger M w（14000） showed a greater KDOM（2.02×10 5） than that with smaller Mw did,and the KDOMs were 1.16×105 and 1.13×105 for the fractions with M w of 1000―14000 and 1000,respectively.The K DOM s of different M w DOM fractions were correlated positively with the atomic ratio of C/H and absorbance at 280 nm;while a negative correlation existed between K DOM and（O＋C）/N（atomic ratio）,and K DOM and O-containing groups.These correlations indicate the positive influence of aromatic structure and the negative effect of polarity on DOM binding capacity.Infrared spectroscopy revealed that specific interactions existed between pyrene and the DOM fraction with larger M W besides hydrophobic partition,i.e.,NH-π interaction in DOM moiety（1000―14000） and π-π electron donor acceptor（EDA） forces in DOM moiety（14000）.KDOM varied in a complex pattern with increasing cation concentration and pH,which could be explained by the change in DOM steric conformation.Formed aggregates favored the lipophilic partition of pyrene.However,the accessibility to some interior binding sites became low when the aggregate was too large,leading to a reduced KDOM.
