[Activity and properties of alkaline phosphatase in the plasma and various organs (kidney, liver, small intestine mucosa, bone) of the swine].

There was a high activity of alkaline phosphatase in the blood plasma of piglets during the first few days of live; enzyme obtained at this time had high heat stability and was readily inhibited by L-phenylalanine (5 mM). The enzyme in blood was inhibited to a greater extent than alkaline phosphatase from intestinal mucosa. With increasing age there was a fall in heat stability and in the ease with that the enzyme could be inhibited by phenylalanine. The proportion of alkaline phosphatase derived from bone and present in blood plasma increased with increasing age. Two isoenzymes were detected in liver, kidney, lung, intestinal mucosa and endometrial mucosa by electrophoresis in polyacrylamide gel. Heat lability and inhibition by phenylalanine were good criteria for differentiating different types of alkaline phosphatase in pigs. In the case of alkaline phosphatase in blood plasma, disodium phenylphosphate was split more readily than p-nitrophenyl phosphate and very much more readily than phenolphthalein diphosphate and beta-glycerophosphate.