On the purification of the alkaline phosphatase of swine kidneys

Abstract

Recent attempts in this laboratory to obtain purified alkaline phosphatase from swine kidney cortex, using the procedure of Albers and Albers were singularly unsuccessful, although the procedure readily gave purified preparations from sheep and horse kidneys. Varying the conditions of the autolysis were without effect on this result. Autolysis of a 1.1 mixture of swine and horse kidney cortex gave results indicating that the enzyme from horse kidney was solubilized and purified at the same time that there was no effect on the enzyme of swine kidney. Further investigation showed that organic solvent extraction removed or destroyed the interference present in fresh swine kidneys. From this it seems likely that an excess of fatty material in the swine kidneys was interfering with the isolation, although other organic solvent effects have not been ruled out. A procedure was developed for the isolation of alkaline phosphatase from fresh swine kidney cortex which avoided the difficulty mentioned above. Principles employed were pancreatin solubilization, ammonium sulfate fractionation, alcohol fractionation and selective denaturation, followed by dialysis. Specific activity of the material obtained is comparable with that of other kidney alkaline phosphatase preparations reported in the literature.