Zhang Hai-Rong, Guo Si-Yuan, Li Lin, Cai Miao-Yan
College of Food and Bioengineering, South China University of Technology, Guangzhou 510640, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2003 Nov;59(13):3185-91. doi: 10.1016/s1386-1425(03)00137-9.
The influence of different denaturants on the phosphorescence spectrum and lifetime decay of Escherichia coli alkaline phosphatase (AP) was investigated. Phosphorescence intensity and lifetime of tryptophan residue (Trp-109) decrease upon addition of guanidine hydrochloride, ethylene diamine tetraacetic acid, and urea or decreasing acidity. The experiments show that AP undergoes different pathways with different denaturants and that the activation energy data, DeltaS degrees (not equal) and deltaH degrees (not equal) further confirm that there is a stable intermediate state between the folded and unfolded AP states in solution.
