4-AZIDOANILINE, A VERSATILE PROTEIN AND PEPTIDE MODIFYING AGENT FOR PHOTO AFFINITY LABELING

A modified synthesis of 4‐azidoaniline and the use of this compound as a protein and peptide modifying agent for photoaffinity labeling is described. 4‐Azidoaniline was diazotized to 4‐azidophenyldiazonium and coupled to N‐acetyl‐tyrosine‐ethylester, and to a tyrosine containing analog of bradykinin. It is shown that the 4‐azidoaniline reagent offers great advantages over other protein modifying agents for photoaffinity labeling, i.e., very high nitrene reactivity, possibility of tritium or iodine labeling, ligand‐receptor complex can be cleaved after isolation. The biological activity of the modified bradykinin analog is measured on rabbit aorta strip in the dark and is similar to the unsubstituted analog. Under the influence of light the modified peptide is able to block partially the myotropic action of bradykinin. Copyright © 1979 Verlag GmbH & Co. KGaA, Weinheim