Effect of PbII on the secondary structure and biological activity of trypsin.
The effects of Pb(II) on the secondary structure and biological activity of trypsin have been examined by monitoring changes in its conductivity and IR and circular dichroism (CD) spectra. The results show that Pb(II) reacts with trypsin, and that the binding sites might be -OH and -NH groups in pepsin. The CD spectra indicate that interaction with Pb(II) significantly affects the secondary structure of trypsin, the beta-sheet-structure content being increased by about 42%, whilst those of alpha-helix and beta-turn structures are decreased by 13% and 21%, respectively. The results clearly demonstrate that Pb(II) affects the biological activity of trypsin by modifying its secondary structure. Most interesting is that Pb(II) up-regulates the activity of trypsin at low concentrations while down-regulating it at high concentrations.
Yang
Lin
L
College of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007, P. R. China. yanglin18@hotmail.com
Gao
Zhiyong
Z
Cao
Ying
Y
Xing
Ruimin
R
Zhang
Xiuying
X
D001665:Binding Sites; D002413:Cations, Divalent; D002942:Circular Dichroism; D007854:Lead / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013329:Structure-Activity Relationship; D014357:Trypsin / Q000737:chemistry* / Q000378:metabolism
D002413:Cations, Divalent; D007854:Lead; D014357:Trypsin