Chemical and mass spectrometry characterization of the red alga Pyropia?yezoensis chemoprotective protein (PYP): Protective activity of the N?terminal fragment of PYP1 against acetaminophen?induced cell death in Chang liver cells

摘要

In the present study, the chemical structure and chemoprotective activity of Pyropia yezoensis protein (PYP) were investigated using sodium dodecyl sulfate (SDS)?polyacrylamide gel electrophoresis, automated protein sequencing, matrix?assisted laser desorption/ionization?quadrupole ion trap?time?of?flight mass spectrometry and a chemoprotective assay using a synthetic peptide. The PYP fraction was demonstrated to contain two proteins: PYP1 (10 kDa, SDS?resistant dimer) and PYP2 (10?kDa). PYP1 is a novel protein showing sequence homology with the hypothetical function?unknown proteins of Chondrus crispus (Rhodophyta) and Emiliania huxleyi (Haptophyceae). PYP2 is a paralog of an extrinsic protein of photosystem?II found in other Rhodophyta. The synthetic peptide PYP1?(1?20), corresponding to the N?terminal 20?residues of PYP1 (ALEGGKSSGGGEATRDPEPT), exhibits chemoprotective activity against acetaminophen?induced cell death in Chang liver cells, indicating that PYP1 is a chemoprotectant of the PYP fraction. A possible association between the structure of PYP and its chemoprotective activity is discussed.