SIMULTANEOUS PURIFICATION OF BIOTIN-BINDING PROTEINS-I AND PROTEINS-II FROM CHICKEN EGG-YOLK AND THEIR CHARACTERIZATION

Chicken egg yolk biotin-binding protein-I (BBP-I) has been purified to homogeneity along with the tetrameric BBP-II by a common protocol. Th e purification includes delipidation of egg yolk by butanol extraction , DEAE-Sephacel chromatography, treatment with guanidinium chloride an d biotin-aminohexyl-Sepharose affinity chromatography. The identity of purified BBP-I was ascertained by its physicochemical properties as w ell as by its immunological cross-reactivity and precursor-product rel ationship with BBP-II.