title: Rapid oxime and hydrazone ligations with aromatic aldehydes for biomolecular labeling.
abstract: A high-yielding and rapid chemoselective ligation approach is presented that uses aniline catalysis to activate aromatic aldehydes toward two amine nucleophiles, namely, 6-hydrazinopyridyl and aminooxyacetyl groups. The rates of these ligations are resolved for model reactions with unprotected peptides. The resulting hydrazone and oxime conjugates are attained under ambient conditions with rate constants of 10(1)-10(3) M(-1) s(-1). These rate constants exceed those of current chemoselective ligation chemistries and enable efficient labeling of peptides and proteins at low muM concentrations, at neutral pH, without using a large excess of one of the components. The utility of the approach is demonstrated by the p-fluorobenzylation of human serum albumin and by the fluorescent labeling of an unprotected peptide with Alexa Fluor 488.
authors.affiliation: Department of Cell Biology, Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, California 92037, USA.
authors.forename: Anouk
authors.initials: A
authors.lastname: Dirksen
authors.forename: Philip E
authors.initials: PE
authors.lastname: Dawson
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000625:Aminooxyacetic Acid / Q000737:chemistry; D000814:Aniline Compounds / Q000737:chemistry; D002384:Catalysis; D006801:Humans; D006835:Hydrazones / Q000737:chemistry*; D010084:Oxidation-Reduction; D010091:Oximes / Q000737:chemistry*; D010455:Peptides / Q000378:metabolism; D011728:Pyridones / Q000737:chemistry / Q000378:metabolism; D012709:Serum Albumin / Q000378:metabolism; D013194:Staining and Labeling / Q000379:methods*; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: D000447:Aldehydes; D000814:Aniline Compounds; D006835:Hydrazones; D010091:Oximes; D010455:Peptides; D011728:Pyridones; D012709:Serum Albumin; D000625:Aminooxyacetic Acid; C023650:aniline