Expression and characterization of recombinant human secretory leukocyte protease inhibitor (SLPI) protein from Pichia pastoris

Zhiguo Li, Allison Moy, Kirti Sohal, Carolyn Dam, Peter Kuo, James Whittaker, Mei Whittaker, Nejat Düzgünes, Krystyna Konopka, Andreas H. Franz, Joan Lin-Cereghino, Geoff P. Lin-Cereghino

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


The human secretory leukocyte protease inhibitor (SLPI) has been shown to possess anti-protease, anti-inflammatory and antimicrobial properties. Its presence in saliva is believed to be a major deterrent to oral transmission of human immunodeficiency virus-1. The 11.7 kDa peptide is a secreted, nonglycosylated protein rich in disulfide bonds. Currently, recombinant SLPI is only available as an expensive bacterial expression product. We have investigated the utility of the methylotrophic yeast Pichia pastoris to produce and secrete SLPI with C-terminal c-myc and polyhistidine tags. The post-transformational vector amplification protocol was used to isolate strains with increased copy number, and culturing parameters were varied to optimize SLPI expression. Modification of the purification procedure allowed the secreted, recombinant protein to be isolated from the cell-free fermentation medium with cobalt affinity chromatography. This yeast-derived SLPI was shown to have an anti-protease activity comparable to the commercially available bacterial product. Thus, P. pastoris provides an efficient, cost-effective system for producing SLPI for structure function analysis studies as well as a wide array of potential therapeutic applications.

Original languageEnglish (US)
Pages (from-to)175-181
Number of pages7
JournalProtein Expression and Purification
Issue number2
StatePublished - Oct 2009
Externally publishedYes


  • HIV
  • Human secretory leukocyte protease inhibitor
  • Pichia pastoris
  • Recombinant protein
  • SLPI

ASJC Scopus subject areas

  • Biotechnology


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