Detection of glycosaminoglycans at the one-nanogram level by 125I-cytochrome c

The basic protein cytochrome c forms stable ionic complexes with all known glycosaminoglycans. When labeled with 125I, cytochrome c is capable of detecting exceptionally small quantities of glycosaminoglycans. Subsequent to electrophoresis on cellulose acetate strips using pyridine formate buffer at pH 3, followed by ethanol fixation, and treatment with 125I-cytochrome c, all the known glycosaminoglycans are detected at minimum levels of 1 ng/0.25-microliter application. The method can be used for quantification of glycosaminoglycans in other electrophoretic buffer systems also.