Expression of Human Insulin-like Growth Factor I in Methylotrophic Yeast Pichia pastoris GS115

The gene encoding human insulin-like growth factor I (huIGF-I) was modified with PCR site-mutation technique and ligated to pGEMT vector and sequenced. Then the yeast expression vector pGaAIGF-I was constructed and transformed to P. pastoris GS115. The expressed huIGF-I reached to 15% of the total soluble yeast proteins and had bioactivity of promoting proliferation of Balb/3T3 cells.