Cl . the Phosphoric - Esterase of Blood

IN a previous communication [Martland and Robison, 1924] it was shown that after blood has been laked with distilled water a rapid increase in the amount of inorganic phosphate occurs even at room temperature. The change is still more rapid at 370 but is entirely inhibited when the blood is laked with 1 00 trichloroacetic acid, which indicates that it is due to the enzymic hydrolysis of phosphoric esters in the blood. The possibility that in these esters the phosphoric acid is combined with sugar or a sugar derivative suggested that this enzyme (both in its hydrolytic and synthetic function) might play a part in carbohydrate metabolism. We have therefore continued the investigation of its properties and have also sought for any changes in the blood sugar which might be correlated with the action of this enzyme on the organic phosphates. In the first place our plan was to find the optimum conditions for the hydrolysis and if possible also for synthesis of the blood phosphoric esters by the enzyme, the location of the enzyme (whether in plasma or corpuscles) and the type of phosphoric ester which it can hydrolyse. It was also of interest to find whether the organic phosphate of blood, which is hydrolysed by this enzyme, is the same as that which is acted on by bone and whether any increase occurs in the reducing sugar of the blood as the result of the hydrolysis. The presence of this phosphoric esterase in blood has been also noticed by Lawaczeck [1924] whose paper did not come to our notice until most of our experiments were completed. With regard to certain of the conditions affecting these enzymic reactions his results are similar to those which we have obtained using different methods. He also gives interesting data with regard to the influence of different ions and of CO2 on the action of the enzyme. Some of these experiments we have repeated and confirmed. His paper does not deal with the question of glycolysis.