Isolation and quantification of alginate-derived oligouronic acids by fluorophore-assisted carbohydrate electrophoresis

Alginate-derived oligouronic acids were analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE). Oligoguluronic acids and oligomannuronic acids were labeled with 8-aminonaphthalene-1,3,6-trisulfonic acid (ANTS) and were separated by polyacrylamide gel electrophoresis. The mobilities of oligoguluronic acids and oligomannuronic acids were much higher than those of maltooligosaccharides, and the best resolution of oligouronic acids having DPs lower than 10 was achieved on 40% polyacrylamide gel. Over the range 0.25 to 4 nmol, the fluorescence intensity of an ANTS-labeled oligouronic acid band could be correlated linearly to the quantity of the oligouronic acid. The distribution of DPs of polyguluronic acid and polymannuronic acid also were estimated by using FACE.