Urea, MP Biomedicals™

Urea in solution is in equilibrium with ammonium cyanate. The form that reacts with protein amino groups is isocyanic acid. Urea in the presence of heat and protein leads to carbamylation of the proteins.

• Carbamylation by isocyanic acid interferes with protein characterization because isocyanic acid reacts with the amino terminus of proteins, preventing N-terminal sequencing
• Isocyanic acid also reacts with side chains of lysine and arginine residues, resulting in a protein that is unsuitable for many enzymatic digests
• Carbamylation often leads to confusing results from peptides having unexpected retention times and masses

Urea is a mild agent usually used for the denaturation of proteins and as a mild solubilization agent for insoluble or denatured proteins. It is also useful for renaturing proteins from samples already denatured with 6M guanidine chloride, such as inclusion bodies.

• It may be used with guanidine hydrochloride and dithiothreitrol (DTT) in the refolding of denatured proteins into their native or active form
• It is commonly used in the extraction of the mitochondrial complex, in isoelectric focusing and two-dimensional electrophoresis, and in acetic acid-urea PAGE gels

Other applications include:

• In cell or tissue culture media, to increase the osmolality
• As fertilizer, because of the easy availability of nitrogen
• In animal feeds
• Reacted with aldehydes to make resins and plastics
• Condensed with malonic ester to form barbituric acid
• In the paper industry, to soften cellulose
• As a diuretic
• To enhance the action of sulfonamides
• As an antiseptic