Total chemical synthesis of deglycosylated human erythropoietin

For the first time the total chemical synthesis of deglycosylated human erythropoietin is described. Synthesis of this 166 amino acid protein, molecular weight 18 389 daltons, was achieved by automated synthesis on the solid phase by stepwise elongation with fluoren-9-ylmethoxycarbonyl amino acids. A novel coupling reagent ethyl 1-hydroxy-(1H)-1,2,3-triazole-4-carboxylate in conjunction with diisopropylcarbodiimide was employed for carboxy activation and tetrabenzo[a,c,g,i]fluoren-17-ylmethoxycarbonyl, a hydrophobic, chromatographic probe which has an affinity for charcoal, aided the purification immensely.