UNIT 15.2 Modification of Amino Groups
Published Online: 1 MAY 2001
Copyright © 2003 by John Wiley and Sons, Inc.
Lab Protocol Title
Current Protocols in Protein Science
How to Cite
Geoghegan, K. F. 2001. Modification of Amino Groups. Current Protocols in Protein Science. 4:15.2:15.2.1–15.2.18.
- Published Online: 1 MAY 2001
- Published Print: JUN 1996
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This unit describes group-specific modifications of amino groups. These reactions remain valid tools for early-stage evaluation of structure-function relationships, but are now valued even more for their applications in the preparation of bioconjugates, affinity columns, biosensors, and tagged macromolecules. Protocols are provided here for reaction of amino groups with succinimidyl esters and isothiocyanates. These methods are broadly useful for the stable coupling to proteins of groups with useful, non-native functional properties. These include biotin for detection or recovery, fluorescent groups for biophysics or cytochemistry, cross-linking reagents for making bioconjugates, or metal-chelators that permit proteins to be loaded with radioisotopes for medical imaging or antitumor therapy. These applications require accurate product characterization, which preferably is performed by mass spectrometry, as described in this unit as a support procedure. A protocol employing succinic or acetic anhydrides to change the charge state of protein amino groups is provided here, as is a procedure for reductive alkylation that leaves their charge unaltered but converts primary amines to secondary or tertiary amines.