High levels of apolipoproteins found in the soluble fraction of avian cornea

Water-soluble proteins in avian corneas were profiled by two-dimensional electrophoresis and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Comparative protein profiling of avian and mammalian corneas revealed five major protein spots specifically detected in avian species. These proteins were identified as apolipoproteins A1 and D by tandem mass spectrometry sequencing. This is the first report of the presence of apolipoproteins in avian cornea. These results could provide insight into the role of lipid metabolism in the avian-specific function of cornea.