Fmoc arg tbu oh

The GCPF peptide was chemically synthesized using Fmoc solid-phase peptide synthesis (SPPS). Briefly, Fmoc-Arg(OtBu)-Wang resin used as a solid-phase material was sequentially coupled to the protected amino acids: Fmoc-Gly-OH, Fmoc-Asn(Trt)-OH, Fmoc-Phe-OH, Fmoc-Arg(tBu)-OH, Fmoc-Trp-OH, Fmoc-Pro-OH and Fmoc-Arg(tBu)-OH (Sigma, USA). The coupling reactions were performed with HOBt/DIC (1.1/1.5, v/v). After all reactions were complete, the synthesized peptide was cleaved from the resin with the lysate solution (TFA/phenol/water/thioanisole/EDT, 92:2.5:2.5:1.5:1.5, v/v/v/v). Then, the purity of synthesized polypeptide was determined using high-performance liquid chromatography (HPLC) on an Amethyst C18-H column (150 mm×4.6 mm i.d., 5 μm, Sepax, USA) with a gradient elution using buffer A (0.1% trifluoroacetic acid (TFA) in 100% water (v/v)) and buffer B (a mixture of 0.1% TFA in 80% acetonitrile and 20% water (v/v)) as the mobile phase at a flow-rate of 1.0 mL/min and UV detection at 220 nm. The gradient started from 28% and ended at 48% of buffer B. Then, the purity of the synthesized polypeptide was determined confirmed to be more than 97.5%.