1993 Volume 22 Issue 2 Pages 93-98
Purification of a recombinant human thyroid-stimulating hormone (rhTSH) was carried out, which was produced in Chinese hamster ovary cells by co-expression of complementary deoxyribonucleic acid for human chorionic gonadotropin (hCG) α and hTSH β subunit as previously described. The cell culture medium was treated by successive chromatographies on S-Sepharose, DEAE-Sepharose, concanavalin-A Sepharose, TSK-G2000SW, and Bio-Gel P-30. Each separation step was monitored by immunoradiometric assay for hTSH. A unique property of rhTSH was observed in the size exclusion chromatography using TSKG2000SW with its flow grossly retarded in the gel. But at the final step by Bio-Gel P-30 column, a single peak of rhTSH with 95% purity was obtained at a position corresponding to the molecular size of pituitary derived authentic hTSH. The overall recovery rate of hTSH immunoreactivity was 10%.
On Western blotting, bands of both the purified rhTSH and a pituitary-derived reference hTSH migrated to the position twice of their molecular weight, showing their tendency of aggregation under a non-reducing condition.
The purification procedures for rhTSH reported here will be applicable to a larger scale production because of its relative simplicity and practical yield.
