Colloid osmotic pressure of steer crystallins : implications for the origin of the refractive index gradient and transparency of the lens

摘要: The osmotic behavior of soluble cortical and nuclear steer lens crystallins was characterized by secondary osmometry for several ionic strength pH conditions. Osmotic pressure versus protein concentration relationships were measured pressures up to 1.15 × 106 dyn cm−2. At low concentrations ( m strength, the observed 0.43 g ml−1 proteins 0.52 proteins. For both crystallins, rose more steeply with than do calf described in literature. impact these developmental differences on transparency is discussed. Both exhibited strength-dependent shifts their pressure-concentration behavior. 0.02 higher observed, whereas at 0.4 lower a given concentration. also found equilibrate different constant 0.1 over range 4–9, maximum around 5 6 crystallins. Thus, adult bovine extracts are properties, reflecting underlying composition. results experiments suggest that hard-sphere, electrostatic, Donnan forces contribute total colloid However, near physiologic charges screened extent exhibits only minor changes large consistent model where regional variations properties across help support radial refractive index gradient present vertebrate lenses. importance metabolites