SOLID-PHASE PEPTIDE-SYNTHESIS AND BIOLOGICAL-ACTIVITY OF BOVINE THYMOPOIETIN-II (BTP-II)

Bovine thymopoietin (bTP), a 49 amino acid polypeptide, was synthesize d using Merrifield's solid-phase peptide synthesis methodology. The po lypeptide was purified using anion-exchange chromatography and reverse d-phase HPLC and characterized by mass spectrometry and amino acid ana lysis of the full-length peptide and of products derived from digestio n with Staphylococcus aureus V8 protease. The biological activity of t he synthesized product was tested in several assay systems. Synthetic bTP was found to induce the expression of Thy 1.2 antigen on T-lymphoc ytes from athymic mice, in agreement with previous studies on the biol ogical activity of endogenous bTP. Biological activity at skeletal mus cle and neuronal nicotinic acetylcholine receptor sites, as reported b y others for bTP, could not be confirmed in our studies. The absence o f biological activity at nicotinic receptor sites may be related to th e results of a recent report demonstrating the presence of a cobratoxi n-like molecule in preparations of natural bTP. These data indicate th at synthetic peptides have an important role for the evaluation of the specificity of the biological activity of polypeptides. (C) Munksgaar d 1994.