Properties of an interphotoreceptor retinoid-binding protein from bovine retina.

摘要: Washes and extracts of frozen fresh cattle retina contain a water-soluble high-molecular-weight, retinoid-binding protein that is distinct from three other proteins previously isolated this tissue. The can be purified to apparent homogeneity retinal homogenates by combination gel filtration, lectin, ion-exchange chromatography. Overestimation the molecular weight was observed in several systems involving migration through porous network. approximate obtained sodium dodecyl sulfate-polyacrylamide electrophoresis 140,000, value consistent with those reported laboratories. However, more detailed analysis using method Ferguson revealed behave anomalously relative used as standards. radius native protein, estimated calibrated corresponded globular 240,000-280,000, suggesting dimer. when interphotoreceptor (IRBP) determined no shape dependence, sedimentation equilibrium, 131,700 +/- 3,900 g/mol, obtained. Sedimentation equilibrium dissociating solvent (6 M guanidine HCl) yielded smallest component 120,100 2,300 g/mol. similarity values for denatured demonstrates monomer. In further support this, evidence dimer cross-linking experiments dimethyl suberimidate. coefficient (S0(20),w = 5.73 0.15 S) were employed calculate frictional Stokes IRBP (f/f0 1.64, Rs 55 A). high f/f0 provides reasonable explanation over-estimation on filtration. Approximately 2 mol exogenous all-trans- or 11-cis-retinol bound per (131,000). 7% binding sites saturated endogenous ligand (11-cis-retinol, 88%; all-trans-retinol, 12%) following isolation partially bleached eyes.(ABSTRACT TRUNCATED AT 400 WORDS)