Carbonyls (–CHO): Ketone or aldehyde groups can be created in glycoproteins by oxidizing the polysaccharide post-translational modifications (glycosylation) with sodium meta-periodate.Ĭrosslinkers are selected on the basis of their chemical reactivities (i.e., specificity for particular functional groups) and other chemical properties that affect their behavior in different applications:.These must be reduced to sulfhydryls to make them available for crosslinking by most types of reactive groups. Often, as part of a protein's secondary or tertiary structure, cysteines are joined together between their side chains via disulfide bonds (–S–S–). Sulfhydryls (–SH): This group exists in the side chain of cysteine (Cys, C).Like primary amines, carboxyls are usually on the surface of protein structure. Carboxyls (–COOH): This group exists at the C-terminus of each polypeptide chain and in the side chains of aspartic acid (Asp, D) and glutamic acid (Glu, E).Because of its positive charge at physiologic conditions, primary amines are usually outward-facing (i.e., on the outer surface) of proteins thus, they are usually accessible for conjugation without denaturing protein structure. Primary amines (–NH2): This group exists at the N-terminus of each polypeptide chain (called the alpha-amine) and in the side chain of lysine (Lys, K) residues (called the epsilon-amine).In fact, just four protein chemical targets account for the vast majority of crosslinking and chemical modification techniques: Despite the complexity of protein structure, including composition and sequence of 20 different amino acids, only a small number of protein functional groups comprise selectable targets for practical bioconjugation methods.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |