title: Synthesis of affinity-label chelates: a novel synthetic method of coupling ethylenediaminetetraacetic acid to amine functional groups.
abstract: An affinity-label chelate for the enzyme trypsin was synthesized by a novel synthetic technique which takes advantage of the presence of a dangling carboxylate arm in the [Co(EDTA)Cl]2- complex anion. The dangling carboxylate group was coupled to the amino group of p-aminobenzamidine, an effective inhibitor of trypsin activity, via the carbodiimmide reaction to produce a trypsin affinity label at one end and a strong EDTA-like chelating agent at the other, coupled through an amide bond. The cobalt ion can be removed if desired by reduction with Fe2+ + ascorbate, and alternate metal ions inserted in its place. The reaction is general, and affinity labels which contain amino groups can be easily coupled via this procedure, allowing the introduction of a paramagnetic or fluorescent probe into a protein or nucleotide system. The same method has been used to prepare a highly effective chelating gel which is capable of removing calcium and lanthanide ions from the binding protein parvalbumin.
mesh_terms: D000345:Affinity Labels / Q000138:chemical synthesis*; D000578:Amidines / Q000138:chemical synthesis; D000588:Amines / Q000032:analysis*; D001550:Benzamidines / Q000138:chemical synthesis; D002614:Chelating Agents / Q000138:chemical synthesis*; D055598:Chemical Phenomena; D002621:Chemistry; D002845:Chromatography / Q000379:methods; D004492:Edetic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008667:Metalloproteins / Q000032:analysis; D013053:Spectrophotometry / Q000379:methods; D013055:Spectrophotometry, Infrared
chemical_list: D000345:Affinity Labels; D000578:Amidines; D000588:Amines; D001550:Benzamidines; D002614:Chelating Agents; D008667:Metalloproteins; C006500:4-aminobenzamidine; D004492:Edetic Acid