Kidney Phosphatase

DURING the past few years much attention has been directed towards the acid-soluble phosphorus compounds present in muscle and in the blood, and to the related synthetic'and hydrolytic systems. There are present in each of these tissues at least two forms of organic phosphorus compounds which are not precipitated on acidification, and which are in equilibrium, in vivo, with the inorganic phosphate present. This equilibrium is controlled by balanced synthetic and hydrolytic systems, both of which, by suitable means, can be shown to exist. The synthetic system, which brings about the esterification of inorganic phosphoric acid is, in each case, more closely associated with the living tissue, though not with the integrity of the cells, than is the hydrolytic, and is much more readily destroyed. Embden and his fellow workers found that in the presence of certain salts such as sodium fluoride and calcium chloride, the synthetic activity of fresh muscle, or muscle juice, outweighs the hydro- lytic, whilst Lawaczeck [1924] and Martland, Hansman and Robison [1924] have demonstrated the presence of a synthetic system in recently shed blood. Martland [1925] has shown how delicately balanced is the equilibrium between organic and inorganic phosphorus in blood, slight alterations from the normal hydrogen ion concentration of the blood bringing about either synthesis or hydrolysis. Alkalinity favours the former, and acidity the latter.