Concanavalin A-agarose removes mannan impurities from an extracellularly expressed Pichia pastoris recombinant protein.

Pichia pastoris secretes few native proteins. However, the more than 1 g l(-1)of extracellularly expressed mannan interfered with the purification of our extracellularly expressed, non-glycosylated recombinant protein. Concanavalin A-agarose removed more than 95% of the unwanted mannan as monitored by phenol reaction. A(13)C-based NMR assay confirmed this improvement. Concanavalin A-agarose can assist the purification of extracellular expressed, non-glycosylated proteins from yeasts.