Different lectin affinities in rat alkaline phosphatase isozymes: multiple forms of the isozyme isolated by heterogeneities of sugar moieties.

Differences among rat alkaline phosphatases from various organs were established by using the serial lectin affinity technique. Elution profiles of isozymes with various lectin columns were significantly different from each other, and it was possible to distinguish between isozymes by this technique. It has been shown by many workers that a high-mannose-type and/or hybrid-type sugar chain is contained in the fraction bound strongly to concanavalin A-Sepharose. The duodenal alkaline phosphatase had a low content of this fraction, although the content of this fraction obtained from duodenal explants was increased markedly when explants were cultured with swainsonine, which is an inhibitor of alpha-mannosidase II, and this leads to the accumulation of high-mannose-type and hybrid-type sugar chains in the pathway of sugar chain processing. From the present results, it is suggested that differences in the elution profiles of isozymes may be due to the structural differences of sugar chains in alkaline phosphatases.