The nature of the cross-linking of proteins by glutaraldehyde. Part 2. The formation of quaternary pyridinium compounds by the action of glutaraldehyde on proteins and the identification of a 3-(2-piperidyl)-pyridinium derivative, anabilysine, as a cross-linking entity

Abstract

1-(5-Amino-5-carboxypentyl)pyridinium chloride (3) and 1-(5-amino-5-carboxypentyl)-3-[1-(5-amino-5-carboxypentyl)-2-piperidyl]pyridinium chloride, anabilysine (4), have been isolated from acid hydrolysates of glutaraldehyde-treated ovalbumin and their structures confirmed by synthesis. It is concluded that the strong chromophore at ca. 265 nm shown by glutaraldehyde-treated proteins is due to the formation of such quaternary pyridinium compounds and that anabilysine residues are important in the cross-linking of proteins by glutaraldehyde.