Incidence and some properties of an electrophoretically slow form of alkaline phosphatase in sera of patients with diseases of the intestine.

A zone of alkaline phosphatase activity migrating at about 40 percent of the rate of liver phosphatase in gel electrophoresis has been detected in sera from 2 out of 22 cases of ulcerative colitis and 1 out of 32 cases of Crohn's disease, but in no other specimen from 33 patients with other diseases of the digestive tract. This rare form of alkaline phosphatase was unlike small-intestinal alkaline phosphatase in several properties. Its appearance in association with diseases of the colon suggests that the rare isoenzyme may originate in that organ. However, the slowly migrating alkaline phosphatase was equally prominent in serum specimens taken before and after operation in one patient who underwent a pan-proctocolectomy for the alleviation of uncontrollable ulcerative colitis.