How Proteins cleaved with Cyanogen bromide

Cyanogen bromide is often used to immobilize proteins by coupling them to reagents such as agarose for affinity chromatography. Because of its simplicity and mild pH conditions, cyanogen bromide activation is the most common method for preparing affinity gels. Cyanogen bromide is also often used because it reacts with the hydroxyl groups on agarose to form cyanate esters and imidocarbonates. These groups are reacted with primary amines in order to couple the protein onto the agarose matrix, as shown in the figure. Because cyanate esters are more reactive than are cyclic imidocarbonates, the amine will react mostly with the ester, yielding isourea derivatives, and partially with the less reactive imidocarbonate, yielding substituted imidocarbonates. The disadvantages of this approach include the toxicity of cyanogen bromide and its sensitivity to oxidation. Also, cyanogen bromide activation involves the attachment of a ligand to agarose by an isourea bond, which is positively charged at neutral pH and thus unstable. Consequently, isourea derivatives may act as weak anion exchangers. Cyanogen bromide hydrolyzes peptide bonds at the C-terminus of methionine residues. This reaction is used to reduce the size of polypeptide segments for identification and sequencing. #NikolaysGeneticsLessons #protein #polypeptide #aminoAcid #peptide #disulfideBridges #covalentBounding #ionicBounding #hydrophobicInteraction #proteinStructure #proteinSequence #proteinFolding #aminoAcids #proteins #Polypeptides #ImidazolRing #Histidine #polypeptideChain #oligopeptide #hydrolysesSynthesis #condensationReaction #condensationSynthesis #peptides #globularProteins #fibrousProteins #Genetics