Protein Post-translational Modification Analysis
Di-Sulfide Bond Localization Services
For many proteins and peptides, disulfide bridges are prerequisite for their proper biological function. Many commercialized proteins are cross-linked by disulfide bridges that increase their resistance to destructive effects of extreme environment used in industrial processes or protect protein-based therapeutics from rapid proteolytic degradation. Manufacturing of these products must take into account oxidative refolding—a formation of native disulfide bonds by specific pairs of cysteines located throughout a sequence of linear protein.
Glycosylation Analysis of Protein
Glycosylation, the attachment of sugar moieties to proteins, is a post-translational modification (PTM) that provides greater proteomic diversity than other PTMs. Glycosylation is critical for a wide range of biological processes, including cell attachment to the extracellular matrix and protein-ligand interactions in the cell. This PTM is characterized by various glycosidic linkages, including N-, O- and C-linked glycosylation, glypiation (GPI anchor attachment) and phosphoglycosylation. Glycoproteins can be detected, purified and analyzed by different strategies, including glycan staining and visualization, glycan cross-linking to agarose or magnetic resin for labeling or purification, or proteomic analysis by mass spectrometry, respectively.
Methylation Services
The transfer of one-carbon methyl groups to nitrogen or oxygen (N- and O-methylation, respectively) to amino acid side chains increases the hydrophobicity of the protein and can neutralize a negative amino acid charge when bound to carboxylic acids. Methylation is mediated by methyltransferases, and S-adenosyl methionine (SAM) is the primary methyl group donor. Methylation occurs so often that SAM has been suggested to be the most-used substrate in enzymatic reactions afterATP. Additionally, while N-methylation is irreversible, O-methylation is potentially reversible.
