Synthetic Studies on Human Transforming Growth Factor(hTGF)-<alpha>

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In 1984, Derynck et al. deduced the primary structure of human TGF-<alph> consisting of 50 amino acid residues with three disulfide bridges by cDNA sequence analysis of it precursor. Because of great interests in biological role of this mitogenic factor associated with cancer cell growth, we undertook the synthesis of human TGF-<alph> both in solution phase and solid phase mehods.1. Solution Phase Synthesis of human TGF-<alph>A protected 50-residue peptide corresponding to the linear sequence of hTGF-<alpha> was prepared by azide condensations of nine peptide fragments of established purity. Amino acid derivatives bearing protecting groups removable by treatment with our newlydeveloped deprotecting reagent, 1 M trimethylsilyl trifluoromethanesulfonate (TMSOTf)/TFA, i.e., Asp(OChp)8 His(Bom), Glu(OBzl), Arg(Mts), Cys(Ad), Tyr(Cl_2-Bzl), Ser(Bzl), Lys(Z).Final deprotection and air oxidation are under investigations.2. Solid Phase Synthesis of Human TGF-<alpha>By using Acm group for the protection of Cys, a 50-residue peptide with eptire sequence of hTGF-was assemhled onto the insoluble polymer support by the Boc-based solid phase procedure, After cleavage of the peptide from the rdsin by 1 M TMSOTf/TFA treatment, the resulting S-Acm derivative was converted to biologically active form by treatment with our newly developed Acm-deprotecting reagent, CF_3SO_3AG, followed by air oxidation.In the mitogenic assay, our synthetic hTGF-<alpha> (10 ng/ml) exhibited the significant soft-agar-colony forming activity of NRK-cells in the presence of hTGF-<beta>.