title: Isolation and preliminary characterization of tear prealbumin from human ocular mucus.
abstract: Tear prealbumin was purified from crude tear prealbumin previously isolated from the saline soluble human ocular mucus. Purification was achieved by further column chromatographies on DEAE Sephadex A-25 and Sephadex G-75. Preliminary characterization included amino acid analysis, gel electrophoresis, and isoelectric focusing. Unlike serum prealbumin, the purified tear prealbumin showed a predominance of acidic residues and a trace amount of tryptophan. It exhibited polymorphic nature, with pI values of 4.8 and 4.9. The possibility of a tear prealbumin/retinol complex was also examined. The protein was found to incorporate with 3H retinol. The 3H retinol-incorporated tear prealbumin did not exhibit the characteristic UV spectrum of retinol; however, it did display emission and excitation fluorescence spectra at high concentrations similar to serum retinol-binding protein.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D055598:Chemical Phenomena; D002621:Chemistry; D005123:Eye / Q000032:analysis*; D006801:Humans; D008970:Molecular Weight; D009093:Mucus / Q000032:analysis*; D011228:Prealbumin / Q000302:isolation & purification* / Q000378:metabolism; D013666:Tears / Q000032:analysis*; D014801:Vitamin A / Q000378:metabolism
chemical_list: D000596:Amino Acids; D011228:Prealbumin; D014801:Vitamin A