Rate of Hydrolysis of Phosphoric Esters of Sugar Derivatives

A number of the components of the tissues contain in their molecules either phosphoric or sulfuric acid. The phosphoric acid radicle is contained in the monoand polynucleotides, and the sulfuric acid radicle in chondroitinand mucoitin-sulfuric acids. In all these compounds the acid radicle is linked in ester form to either a carbohydrate or a polyhydric alcohol. On long acquaintance with substances of this character, one comes to realize that the inorganic radicle is linked in different substances of the same group with different degrees of firmness. Thus, for instance, in inosinic and uridinphosphoric acids on one hand, and in guanylic on the other; in chondroitin-sulfuric on one hand, and in mucoitin sulfuric on the other, the organic acids display different degrees of resistance towards hydrolytic agents. In compounds such as the ribose nucleotides, two components of the molecule, the sugar, and the inorganic acid, remain constant, and only the third component is variable. It is evident that the firmness of the union between the acid and the rest of the molecule may be conditioned by two factors: the character of the base, and the position of the acid radicle on the sugar molecule. There exists no systematic study of the rate of hydrolysis of ester form derivatives of sugars which have only one point of difference; namely, that of the allocation of the acid radicle. However, in the preparative work on sugar derivatives by Fischer1 and his students, and by Irvine2 and his students, one