Alkaline phosphatase. I. Comparison of the physical and chemical properties of enzyme preparations from mammalian cell cultures, various animal tissues, and Escherichia coli

Some of the chemical and physical properties of alkaline phosphatase preparations derived from mammalian tissues, cell cultures, and E. coli have been compared. A number of chemical and physical properties of the various enzyme preparations are similar, such as the concentration of cysteine and histidine that inhibits alkaline phosphatase activity, and the phosphotransferase activity of different enzyme preparations. Other properties of the various alkaline phosphatases are markedly different, such as heat stability at 56 °, electrophoretic mobility, and the concentrations of Zn ions, L-phenylalanine, and L-tryptophan required to inhibit enzyme activity by 50%. These differences provide a means of distinguishing between alkaline phosphatases from different tissues and different species. Some of the physical and chemical characteristics of these enzymes appear to be related to, or coincidently associated with the mechanisms of enzyme regulation observed in cell cultures and in vivo.