Studies on alkaline phosphatases. 3. Influence of age of fowl and mammals on pH optima

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Abstract
The pH optima for the phosphatase of intestinal mucosa of fowl (for the respective concentrations of glycerol 2-phosphate) rose with increasing age of the birds. There were no differences between sexes and among several breeds of 1-day-old chicks. The optimum pH for the intestinal phosphatase of chicks was not affected by the addition of inactivated (heated at 80[degree] for 30 min.) intestinal mucosa of hens, and the optimum pH for the enzyme of mature fowl was not altered by inacti-vated mucosa of chicks. A mixture of the enzyme preparations of chicks and mature fowl exhibited a PH-activity curve and quantitative reaction velocities which would be expected from a combination of 2 enzymes possessing different pH optima. In rabbits the shift in pH optima for intestinal phosphatase was to lower values with increasing age, the major change taking place in the first 2 months of life. There was no change in pH optima of the phosphatase of intestinal mucosa of rats as their age increased from 6 weeks to 1 year. The pH optima for the phosphatase of a preparation of the whole duodenum of 1-day-old rats were higher than those of the mucosal enzyme of older rats. The pH optima for the phosphatases of bone, liver and kidney of fowl and rabbits appeared to be constant regardless of their age.