Application of Fmoc-amino acid carrying an unmasked carbohydrate to the synthesis of the epidermal growth factor-like domain of bovine blood coagulation factor IX.

The epidermal growth factor (EGF)-like domain of the bovine blood coagulation factor IX (45-87) carrying glucose at Ser(53) was synthesized by a solid-phase method using 9-fluorenylmethoxycarbonyl (Fmoc)-amino acids. The introduction of Ser(53) was carried out using the benzotriazolyl ester of Fmoc-serine carrying an unmasked glucose. The remaining sequence was also introduced using the benzotriazolyl ester. HPLC analysis of the crude peptide shows that acylation of the free hydroxyl group of the glucose was not significant, demonstrating that the amino acid carrying an unmasked carbohydrate is a useful building block for solid-phase synthesis.