Off-white to brown powder
The in-vivo incorporation of clickable unnatural amino acids such as 4-Azido-L-phenylalanine with unique reactivity at a defined postition is used for functionalization of proteins. The azide functionalities in the protein can then be modified with almost any alkyne bearing molecule by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). Copper-free alternatives with strained internal alkynes are also available (SPAAC). Some examples enabled with this technique are protein PEGylation, masking with sugars, and the attachment to antibodies.
4-Azido-L-phenylalanine is an unnatural derivative of L-phenylalanine. It is a nonpolar, essential amino acid that naturally occurs in the human body and is also used to treat patients with depression.
