Expression Technologies Inc.

Protein activity

Some recombinant proteins are not biologically active after expression. Functional proteins are essential for certain biochemical analysis. Medium composition, protein folding, and post translation modifications all play important roles in protein function.

All expressed proteins have to be soluble to be functional. More information for protein solubility...

Strategies to produce functional proteins:

	Use special media containing trace metals, minerals and vitamins. These chemicals may not be needed for host cell growth, but they may serve as co-factors, prosthetic groups or ligands for recombinant proteins.
	Co-express the protein with molecular chaperones or its natural partner known to interact with the protein. Many proteins will not be active without its molecular chaperone or natural partner.
	Choose the expression system containing proper post translational modifications such as phosphorylation and glycosylation.
	Re-fold the expressed protein.
	Express the protein with an intact structure or domain.

Some of above strategies can be easily achieved such as using a special medium and co-expressing in existing cell strains. Others such as changing expression system and protein re-folding require more molecular biology manipulation.

Examples:

	Co-expression of nuclear receptor partners in a cell strain increases the solubility of one partner and biological activities of both partners.
	Co-expression of Smyd with hsp90 results in soluble and functional Smyd proteins.
	Expression of nuclear hormone receptor SXR in ProGroTM results in soluble and functional proteins.

We appreciate your comments or feedbacks at info@exptec.com.