Bioconjugation Reaction Of 2-pyridyl Alkyne Unsaturated Compounds With Cysteine

Cysteine exists in 97%of human proteins and exhibits diverse physiological functions due to the unique nature of the sulfur atom in the thiol group.The diverse post-translational modifications of cysteine residues have been reported are related to the physiological and pathological processes of many diseases.Besides,cysteine also plays an important role in cellular anti-oxidant defence mechanisms.The development of bioconjugation for protein cysteine residues has been a hot area of chemical biology research.Herein,we synthesized ten 2-alkynyl pyridine derivatives,and reformed the model reactions between them and N-acetyl-cysteine methyl ester.We investigated the reaction kinetics,specificity,substrate and product stability of this reaction.The results show that this reaction works well with fast reaction rate,good specificity.Both the starting materials 2-alkynyl pyridinone and products are stable under physiological conditions.The western-blot assays further demonstrate that this labeling reaction can be used for the efficiently and highly selectively mapping of proteins with cysteine residues,which reveals its potentiality in ABPP research.We further linked the broad-spectrum anticancer drug doxorubicin(DOX)to 2-alkynyl pyrrolinone to synthesize a stable antibody-drug conjugate precursor,which may promote the development of ADCs and the treatment of cancer.