Structural Characterisation of Human Recombinant Glycohormones Follitropin, Lutropin and Choriogonadotropin Expressed in Chinese Hamster Ovary Cells

The α and β chains from human recombinant gonadotropins follitropin, lutropin and choriogonadotropin expressed in CHO cells have been structurally characterised both at the protein and at the carbohydrate level by using advanced mass spectrometric procedures. The three α chains share the same amino acid sequence while they display different glycosylation patterns. The oligosaccharide structures detected belong to the complex‐type glycans with different degree of sialylation. Partial proteolytic processing occurred at the N‐terminus of the follitropin β chain and at the C‐terminus of the lutropin β chain. The N‐linked glycans from the three β chains were found to contain fucosylated and sialylated diantennary and triantennary complex‐type structures. The follitropin β chain showed the presence of N‐acetyllactos‐amine repeats on the antennae. The overall structure of the recombinant glycohormones corresponds to their natural counterparts with the exception that sulphated terminal glycosylation is missing.