CHARACTERIZATION OF CARBOHYDRATE CHAINS O F 2 FORMS OF HUNCHBACK SALMON GONADOTROPIC HORMONE HAVING DIFFERENT AFFINITY TO CONCANAVALIN-A

A comparative analysis of carbohydrate chains of two forms of hunchbac k salmon gonadotropin that bind or not with ConA-Sepharose was carried out. It was found that unbound, <<protein>>, ConA--form contains thre e times less carbohydrates and has slightly different amino acid compo sition as compared to the bound, normally glycosylated ConA+-form. HPL C fractionation showed the oligosaccharides released from both hormone forms to be mainly sialylated. The major oligosaccharides identified in ConA-form are biantennary, fucosylated (approximately 20%) or nonfu cosylated; minor bissected chains are also present. In ConA--form the same oligosaccharides and also oligosaccharides with a higher degree o f branching (tri- and tetraantennary) were detected. These two hormone forms isolated from pituitary glands of male or female fish differed neither in the type of oligosaccharides nor in their ratio. Essential structural differences in carbohydrate chains of hunchback salmon and sturgeon gonadotropins were distinctly demonstrated.