STRUCTURAL CHARACTERIZATION OF HUMAN RECOMBINANT GLYCOHORMONES FOLLITROPIN, LUTROPIN AND CHORIOGONADOTROPIN EXPRESSED IN CHINESE-HAMSTER OVARY CELLS

The alpha and beta chains from human recombinant gonadotropins follitr opin, lutropin and choriogonadotropin expressed in CHO cells have been structurally characterised both at the protein and at the carbohydrat e level by using advanced mass spectrometric procedures. The three alp ha chains share the same amino acid sequence while they display differ ent glycosylation patterns. The oligosaccharide structures detected be long to the complex-type glycans with different degree of sialylation. Partial proteolytic processing occurred at the N-terminus of the foll itropin beta chain and at the C-terminus of the lutropin beta chain. T he N-linked glycans from the three beta chains were found to contain f ucosylated and sialylated diantennary and triantennary complex-type st ructures. The follitropin beta chain showed the presence of N-acetylla ctosamine repeats on the antennae. The overall structure of the recomb inant glycohormones corresponds to their natural counterparts with the exception that sulphated terminal glycosylation is missing.