The alkaline phosphatases of human liver: an immunochemical study

Four out of 18 human liver alkaline phosphatase (AP) preparations reacted with anti-liver and anti-intestinal AP. The liver AP that reacted with anti-intestinal AP, designated as intestine-like AP, was precipitated at 50% ammonium sulfate whereas the major liver AP precipitated at 66% saturation. Gel filtration showed that liver AP, intestine-like AP and intestinal AP contained AP with apparent molecular weights of 130,000 daltons; the intestine-like AP contained a second but smaller component of 70,000-80,000 daltons. AP extracted from intestine also contained this smaller component; its electrophoretic mobility was that of an a2-globulin, whereas that of the intestine-like AP had a mobility of beta-globulin. The similarity of the intestine-like AP to the AP variant found in hepatomas is stressed.