Separation and identification of carp pituitary proteins and glycoproteins

Abstract

Carp pituitary proteins and glycoproteins were separated by the combination of immobilized metal affinity chromatography (IMAC) and affinity chromatography on Con A-Sepharose. The protein fractions were analysed by SDS-PAGE. Luteinizing hormone (in the α<sub>1</sub>β and α<sub>2</sub>β forms), growth hormone, free α<sub>1</sub> subunit and β subunit of thyroid-stimulating hormone were identified by N-terminal amino acid sequencing. N-linked oligosaccharide chains of thyroid-stimulating hormone (β TSH) were separated after fluorescent labelling on a GlycoSep N column and treated by exoglycosidases. Among the saccharide components, complex and hybrid structures terminating SO<sub>4</sub>-GalNAc-GlcNAc-Man-, and high mannose structures, with 1 to 8 mannose units attached to the oligosaccharide core (GlcNAc)<sub>2</sub>(Man)<sub>3</sub>, were found.