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Hyperexpression of biologically active human chorionic gonadotropin using the methylotropic yeast, Pichia pastoris

Gupta, Sen C and Dighe, RR (1999) Hyperexpression of biologically active human chorionic gonadotropin using the methylotropic yeast, Pichia pastoris. In: Journal of Molecular Endocrinology, 22 (3). pp. 273-283.

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Abstract

Human chorionic gonadotropin (hCG), a heterodimeric glycoprotein hormone, is composed of an alpha subunit noncovalentlv associated with the hormone-specific beta subunit. The objective of the present study was recombinant expression of properly folded, biologically active hCG and its subunits using an expression system that could be used for structure-function studies while providing adequate quantities of the hormone for immunocontraceptive studies. We report here expression of biologically active hCG and its subunits using a yeast expression system, Pichia pastoris. The recombinant hGG alpha and hCG beta subunits were secreted into the medium and the levels of expression achieved at shake culture level were 24 and 2.7-3 mg/l secretory medium respectively. Go-expression of both subunits in the same cell resulted in secretion of heterodimeric hGG into the medium. The pichia-expressed hCG was immunologically similar to the native hormone, capable of binding to the LH receptors and stimulating a biological response in vitro. Surprisingly, the maximal response obtained was twice that obtained with the native hGG. The le level of expression of hCG achieved was 12-16 mg/l secretory medium and is expected to increase several-fold in a fermenter. Thus the Pichia expression system is capable of hyperexpressing properly folded, biologically active hGG and is suitable for structure-function studies of the hormone.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Society for Endocrinology.
Department/Centre: Division of Biological Sciences > Molecular Reproduction, Development & Genetics (formed by the merger of DBGL and CRBME)
Date Deposited: 12 Aug 2009 10:30
Last Modified: 19 Sep 2010 05:29
URI: http://eprints.iisc.ernet.in/id/eprint/19702

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