Proteins are responsible for complex biochemical reactions and have a specific three-dimensional structure when exercising biological functions. In biochemical tests, researchers often need to study the denaturation and renaturation of protein, guanidine hydrochloride and urea are the most commonly used reagents, what is the difference between these two reagents? Which one is better?
There are two mechanisms for protein denaturation by guanidine hydrochloride and urea:
(1) Denatured protein preferentially combines with guanidine hydrochloride and urea to form complexes. With the increasing of denaturant concentration, the protein in natural state changes into complex, resulting in complete denaturation;
(2) The solubilization of guanidine hydrochloride and urea for hydrophobic amino acid residues: Guanidine hydrochloride and urea are able to form hydrogen bonds, which can break in the high concentration (4~8mol/L) aqueous solution to become a better solvent for non-polar residues, so that solubility of protein molecules within the hydrophobic residues increased and degeneration occurs.
What is the differences between guanidine hydrochloride and urea?
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Concentration: At room temperature, 3~4mol/L guanidine hydrochloride can make the globular protein to the midpoint from the natural state to the denaturation state; about 6mol/L guanidine hydrochloride can make the protein completely into degeneration state. While some globular proteins can not be completely denatured even in 8mol/L urea solution.
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Solubility: Urea dissolves slowly and weakly than guanidine hydrochloride. Its solubility is 70%~90%. The solubility of guanidine hydrochloride is more than 95%.
In general, as commonly used reagents in protein denaturation, guanidine hydrochloride (50-01-1) has relatively strong dissolving capacity and denatured ability and does not cause the covalent modification of the recombinant protein, but has the disadvantages of high cost, easy precipitation under acidic conditions, and interference with protein ion exchange chromatography; the solubility of urea is relatively weak, however, it has the advantages of non-ionization, neutrality, low cost, and no protein precipitation after protein renaturation.
Edited by Suzhou Yacoo Science Co., Ltd.
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