The invention discloses a
Pichia pastoris transformant capable of expressing human
recombinant interleukin-3 (rhIL-3) with high efficiency and a purification method thereof. In the method, the eukaryotic host is
pichia pastorisX-33. The purification method comprises the following steps:
cloning a human IL-3
gene; establishing a eukaryotic
expression vector, and transforming the eukaryotic
expression vector into the eukaryotic
yeast host; obtaining a
yeast transformant for high-level secretory expression by screening, wherein the IL-3 expressed by the yeasts are available in a glycosylated mode and a non-glycosylated module; and performing amplified culture by using a
shake flask, and subjecting the supernate of the culture solution to
dialysis,
nickel affinity purification and further purification by diethylaminoethanol (DEAE) anion column. The purified product is subjected to
mass spectrometric identification and analysis, and the result of the
mass spectometric identification and analysis indicates that the expressed IL-3 is modified by different glycosyls and that the IL-3 has an his*6 tag and a C-
MYC tag and is easy for purification and detection of expression product. In the invention, different from the conventional method using a prokaryotic host to express the rhIL-3, the method for expressing a large amount of rhIL-3 by using a
Pichia pastoris expression
system is adopted for the first time, quick purification is realized by using a His-tag
protein, the purified rhIL-3 is high-activity rhIL-3
protein which is glycosylated to different extents and of which the molecular weight is 19kDa and 22kDa. The method ensures that the high-activity rhIL-3 recombinant
protein is obtained quickly.