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Effect of Pb II on the Secondary Structure and Biological Activity of Trypsin
Author(s) -
Yang Lin,
Gao Zhiyong,
Cao Ying,
Xing Ruimin,
Zhang Xiuying
Publication year - 2005
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200400267
Subject(s) - trypsin , protein secondary structure , circular dichroism , chemistry , crystallography , biological activity , stereochemistry , enzyme , biochemistry , in vitro
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 β‐sheet‐structure content being increased by about 42 %, whilst those of α‐helix and β‐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.