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Updated: Apr 17, 2026

Site-Specific Lysine Lactylation via Genetic Code Expansion in E. coli and Mammalian Cells
Published on: February 24, 2026
Molecular cloning, expression and purification of lactoferrin from Tibetan sheep mammary gland using a yeast
Jianbo Li1, Wuzheng Zhu1, Meirong Luo2
1Key Laboratory of Sichuan Province for Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Exploitation, Chengdu 610041, PR China; College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041, PR China.
Abstract:
This paper reports the successful expression of a lactoferrin gene-obtained from the mammary gland tissue of Tibetan sheep-in the yeast Pichia pastoris GS115 using pPICZαA as the recombinant plasmid and α-factor signal sequence for secretion. The recombinant lactoferrin was purified by ammonium sulfate precipitation, ion-exchange column chromatography and gel-filtration chromatography, and it had a molecular mass of 76kDa. We obtained an expression yield of >60mgL(-1) and specific activity of 2533.33Umg(-1). The antimicrobial activities and iron-binding behaviors of recombinant lactoferrin indicated that it was correctly folded and functional. Additionally, recombinant lactoferrin inhibited the growth of Escherichia coli JM109 and Staphylococcus aureus. These findings indicate that recombinant lactoferrin is a potential antibiotic for use on humans. This study also demonstrates the successful expression of recombinant lactoferrin using the eukaryotic host organism P. pastoris, paving the way for protein engineering using this gene.

