The Expression of Human Relaxin in Yeast

The chemically synthesized DNA-coding sequence for an artificial single chain human relaxin consisting of a B chain, an Arg-Arg-Glu-Phe-Lys-Arg-connecting peptide, followed by the A chain, was used to construct two plasmids which were introduced into Saccharomyces cerevisiae. Expression of the relaxin-coding sequence was under the control of either the yeast TDH3 promoter or the CUP1 promoter. The yeast α-factor signal sequence was used to direct the protein into the secretory path, and the appearance of human relaxin in the growth medium was confirmed by radioimmunoassay and immunoblotting. Partially purified human relaxin from yeast was biologically active in the mouse symphysis pubis assay and radioreceptor assay.