Affinity methods with lectins: a tool to identify canine alkaline phosphatase isoenzymes

Affinity methods were used to characterize selective interactions of alkaline phosphatase (ALP) isoenzymes from different dog tissues with lectins. Specific lectins were used to identify liver, intestinal and steroid-induced ALP isoenzymes in serum from dogs with Cushing syndrome or steroid-treated dogs. For the first approach, 12 lectins were assayed by affinity dots. Selective interactions were found among wheat germ agglutinin (WGA), jacalin, con A (concanavalin A) and Helix pomatia agglutinin (HPA) and several ALP-containing samples. These four reactive lectins were assayed by line electrophoresis with lectins in holes. A strong reactivity of con A with all isoenzymes was found, although the patterns were different. WGA interacted with intestinal, bone marrow extracts and Cushing syndrome serum. Jacalin changed the electrophoretic patterns of intestinal and liver ALP, and Cushing serum. Finally, by crossed electrophoresis with lectins in gels, it was possible to distinguish among hepatic or intestinal ALPs and the steroid-induced isoenzyme in serum. Affinity electrophoresis with lectins provided a clear separation and identification of the different dog ALP isoenzymes.