These modifications can reduce overall charges in peptides, on the other hand, they may reduce the water solubility of peptides as well. Since these terminal modifications may increase the stability of peptides, and make peptides fragments closer to their native states in proteins, they may enhance the biological activities of peptides.
Phosphorylation is the main form of reversible covalent modification of proteins for their regulation. This is catalyzed by a large family of enzymes called protein kinases. The dephosphorylation of phosphoproteins is carried out by another group of enzymes called protein phosphatases. The study of these enzymes and their phosphoprotein targets (also known as substrates) is having an enormous impact on our understanding of how cells are controlled and human health care delivery.
Protein methylation typically takes place on arginine or lysine amino acid residues in the protein sequence. Arginine can be methylated once (monomethylated arginine) or twice, with either both methyl groups on one terminal nitrogen (asymmetric dimethylated arginine) or one on both nitrogens (symmetric dimethylated arginine) by peptidylarginine methyltransferases (PRMTs). Lysine can be methylated once, twice or three times by lysine methyltransferases. Protein methylation has been most-studied in the histones.
Sulfation of tyrosine residues is an important post-translational modification that occurs on manysecretory as well as transmembrane proteins. It has been suggested that up to 1% of all tyrosine residues of the overall protein content in an organism are sulfated which makes this modification essential for numerous biological processes. However, one of the factors hindering the study of the significance of sulfotyrosine (sTyr) within a protein is the absence of a general method that enables the synthesis of sTyr peptides in satisfactory yields and purity.
We provide wide range of fluorescence labeling services, which include FITC, MCA, 5(6)-FAM, Dnp, EDANS, Dabcyl, Dansyl, Rhodamine,Bodipy and Pyrene. The list can go on. Please contact us if the fluorescence label of your interest is not on the list.
Cyclic peptides can reduce the backbone flexibility of the linear peptides, therefore increase the rigidity of the molecular and limit the possible conformations of the peptides. These kinds of structural constrain is very important to the structural stability and biological activity.
