THE SECRETION OF HUMAN-SERUM ALBUMIN FROM THE YEAST SACCHAROMYCES-CEREVISIAE USING 5 DIFFERENT LEADER SEQUENCES

We demonstrate the secretion of human serum albumin into the culture supernatant from the yeast Saccharomyces cerevisi- ae. Studies with five KEX2 processed leader sequences, namely the S. cerevisiae a. factor, the natural human serum albumin, the Kluyveromyces lactis killer, a natural human serum albumin/β factor fusion, and a Kluyveromyces lactis killer/β factor fusion leader, are described. We show that the leader sequence used to direct secretion influences the quantity and quality of the secreted product. In designing secretion systems for heterologous proteins, one aims to maximise both the yield and fidelity of the product. Our results indicate that the choice of leader sequence and its relationship to the structural protein under study are crucial to the success of this process. © 1990 Nature Publishing Group.