Solid-phase synthesis of thymosin β10 using a p-cyanotrityl resin. Chemical characterization and immunochemical control of the synthetic peptide

Abstract

Thymosin β₁₀(43 amino acids) was synthesized following the Fmoc-solid-phase strategy, using a new p-cyanotrityl resin. This resin shows enhanced acid stability compared with the usual trityl ester resins, thus providing selective peptide synthesis with high yield and purity. Crude Tβ₁₀ was purified with gel filtration and semi-preparative reversed-phase high-performance liquid chromatography (RP-HPLC). The purified synthetic peptide was shown to co-elute with recombinant Tβ₁₀ in an analytical RP-HPLC system. The amino acid analysis data were in agreement with those reported for the literature primary structure of natural Tβ₁₀. The electrospray ionization mass spectrometry (ESIMS) data showed almost identical average mass (M_{r, exp})-values for the synthetic or the recombinant product, which were in agreement with the molecular mass calculated on the basis of the proposed primary structure for the peptide. Furthermore, the synthetic Tβ₁₀ exhibited similar immunochemical characteristics compared with the recombinant material in an in vitro ELISA test using rabbit polyclonal anti-Tβ₁₀ antiserum.