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Studies on bovine transferrin; isolation and partial characterization
Author(s) -
Efremov G. D.,
Smith Linda L.,
Barton Betty P.,
Huisman T. H. J.
Publication year - 1971
Publication title -
animal blood groups and biochemical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0003-3480
DOI - 10.1111/j.1365-2052.1971.tb01216.x
Subject(s) - transferrin , sialic acid , neuraminidase , sephadex , chromatography , biochemistry , chemistry , bovine serum albumin , biology , enzyme
Summary Bovine serum transferrin (type Tf‐A) was isolated by a series of four techniques; (a) precipitation with Rivanol; (b) chromatography of the soluble protein fraction on a column of Sephadex G‐150; (c) chromatography of the transferrin containing protein zone on a column of DEAE‐Sephadex; and (d) chromatography on a column of DEAE‐Sephadex after transferrin was treated with neuraminidase. It was found that an unidentified protein binds firmly to transferrin, and its removal is only possible after the release of the sialic acid residues with neuraminidase. It is possible that this protein is hemopexin. The occurrence of multiple transferrin components is, in part, dependent on the number of sialic acid residues; possible differences in molecular weight or size seem not to be a factor. The amino acid composition of bovine transferrin, and that of each of three subfractions, resembles that of human transferrin. The calculated mol. wt. of bovine transferrin was found to be 67,000 from sedimentation and viscosity data and 72,400 from sedimentation and diffusion measurements. Sedimentation and viscosity data in concentrated urea suggest that bovine transferrin is composed of two subunits, an observation which is in contrast to data from studies which suggest that human transferrin is composed of a single polypeptide chain.