Synthesis of prothymosin alpha deduced from nucleotide sequence of the murine cDNA and its effect on the impaired T lymphocytes of uremic patients.

The complete murine prothymosin alpha molecule (110 residues) except for the N-terminal methionine deduced from the cloned cDNA has been synthesized by a solid-phase method. Peptide synthesis was performed manually by the stepwise solid-phase method using the base-labile Fmoc group for protecting the alpha-amino group. The peptide was assembled on a p-alkoxybenzyl alcohol resin. After the last coupling step, the Fmoc group was removed with 50% piperidine in DMF. The peptide resin was treated with thioanisole-o-cresol in TFA, and then purified by gel filtration, ion-exchange column chromatography and high-performance liquid chromatography. A 2.9-mg sample of a highly purified peptide was finally obtained. The overall yield of the synthesis was less than 1%, based on the amino acid content of the starting Fmoc-Asp (OtBu)-resin. The synthetic peptide was found to have a restoring activity on low-E-rosette-forming lymphocytes after incubation of peripheral blood from uremic patients with the synthetic peptide. This peptide exhibited far stronger restoring effect than that of our synthetic thymosin alpha 1.