title: Subunit of glycosylation-inhibiting factor is an abundant protein that binds to certain glycoproteins and sugars.
abstract: 12 kDa subunit of glycosylation-inhibiting factor (GIF) is an abundant protein that can be isolated to homogeneity from different mammalian organs by successive application of the carboxymethylcellulose cation exchanger CM52, preparative flat-bed isoelectrofocusing and repeated application of CM52-cellulose. Several isoforms of the 12 kDa GIF subunit exist in mammalian tissues. Conformational stability of two isoforms of a 12 kDa porcine GIF subunit have been studied by CD. Conformation of the protein remains stable within the range 20 degrees to 60 degrees C. Over 60 degrees C the protein undergoes irreversible denaturation. The 12 kDa GIF subunit is not stable within the pH range 2 to 3, adopts quasi-native structure within the pH range 3.5 to 5 while it remains stable between the pHs 6 to 10. The 12 kDa GIF subunit strongly binds to CM52-cellulose from which it can be eluted at concentrations of NaCl higher than 0.6 M. The GIF subunit may also be eluted from the modified cellulose using certain glycoproteins and sugars. High abundance of the 12 kDa GIF subunit in different mammalian tissues and its capacity to bind certain glycoproteins and sugars may suggest that the protein might be involved in regulatory mechanisms of glycoprotein transport (chaperone for glycoproteins) and modulation of interactions between secreted glycoproteins and the cell surface receptors.
authors.affiliation: Departement d'Ingénierie et d'Etudes des Protéines, D.S.V./C.E.A., C.E.-Saclay, Gif-sur-Yvette, France.
authors.forename: A
authors.initials: A
authors.lastname: Galat
authors.forename: F
authors.initials: F
authors.lastname: Bouet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D002645:Chickens; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000378:metabolism*; D006031:Glycosylation; D008222:Lymphokines / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D046911:Macromolecular Substances; D008322:Mammals; D051379:Mice; D008969:Molecular Sequence Data; D029584:Prostatic Secretory Proteins; D011487:Protein Conformation; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013552:Swine
chemical_list: D006023:Glycoproteins; D008222:Lymphokines; D046911:Macromolecular Substances; D029584:Prostatic Secretory Proteins; C043076:beta-microseminoprotein; C013059:immunoglobulin-binding factors