Purification and properties of chicken egg-white cobalamin-binding protein.
A cobalamin-binding protein has been purified from chicken egg-white by using a combination of conventional and high performance ion-exchange chromatography. Following initial purification by DEAE-cellulose, ammonium sulphate precipitation, Sephacryl S-200 CM-cellulose and affinity chromatography, appropriate fractions were further purified using the Pharmacia fast protein liquid chromatography (FPLC) system. Using this method of purification, egg-white CBP has been purified more rapidly and with greater recovery than with conventional column chromatography. The homogeneity of this protein was verified by SDS-PAGE. The Mr was 37,000 by SDS-PAGE and 39,000 by gel filtration, which indicated that it was a glycoprotein. The stokes radius was 4.1 nm and pI was 4.3. The protein bound 57COB12 with a molar ratio of 1/1 and kd of 0.40 microM. The egg-white CBP was composed of 294 amino acid residues. Thiol groups and metal ions were not connected with the Cbl-binding activities.
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Department of Animal Biochemistry, Jagiellonian University, Cracow, Poland.
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D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002645:Chickens; D003208:Concanavalin A; D004527:Egg Proteins / Q000032:analysis / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing / Q000379:methods; D037102:Lectins; D008969:Molecular Sequence Data; D037121:Plant Lectins; D014155:Transcobalamins / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D014805:Vitamin B 12 / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors
D000596:Amino Acids; D004527:Egg Proteins; D037102:Lectins; D037121:Plant Lectins; D014155:Transcobalamins; C036554:dolichos biflorus agglutinin; D003208:Concanavalin A; D014805:Vitamin B 12