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. Author manuscript; available in PMC: 2013 Jun 6.
Published in final edited form as: Methods Mol Biol. 2012;796:117–132. doi: 10.1007/978-1-61779-334-9_7

Table 1.

A partial list of chemical functional groups that are targeted preferentially by reactive amino acid side chains

Functional group Targeting nucleophile Optimal pH Amino acid target
Name Structure
N-Hydroxysuccinimide ester graphic file with name nihms468016t1.jpg Amine >7 Lysine
Protein N-termini
Imido ester graphic file with name nihms468016t2.jpg Amine 8–9 Lysine
Protein N-termini
Maleimide graphic file with name nihms468016t3.jpg Sulfhydryl 6.5–7.5 Cysteine
Cyclohexanedione graphic file with name nihms468016t4.jpg Guanidine >7 Arginine
Phenyl azide graphic file with name nihms468016t5.jpg Amine 7 Cysteine
Phenol Arginine
Double bond Lysine
Histidine
Tyrosine
Phenylalanine
Tryptophan