Robison ester

Glucose-6-phosphate. D-Gfucose 6-<dihydrogen phosphate) glucose-6-phosphoric acid Robison ester. C4-HijOjP mol wt 260.14. C 27-70%, H 5.04%, O 55.35%, P... 

A number of hexose phosphates have been isolated from natural sources. Of these oTructose 1,6-diphosphate (Harden-Young ester) (I), D-fructose 6-phosphate (Neuberg ester) (II), D-glucose 6-phosphate (Robison ester) (III), and a-D-glucose 1-phosphate (IV) are of particular biochemical importance in the processes of fermentation and glycolysis. These hexose phosphates are interconvertible in the presence of the proper enzymes and cofactors. 

Glucose-6-phosphate Robison ester)—Although the existence of this ester had been known since 1914 from experiments on yeast carried out by Harden and Robison, it was not until 1931 that Robison and King succeeded in obtaining it in the pure state. 

It has long been known that fermentation by yeast extracts normally comprises at least three phases an initial induction period followed, within a matter of about five or ten minutes, by a very rapid fermentation this persists for some time and passes over into a prolonged relatively slow action. All this has been measured by carbon dioxide production. This is true not only for glucose, shown, e.g., by Meyerhof (53,54), but also for galactose (40) and for fructose (34). These have been attributed to the formation of the hexose-6-phosphate (Robison ester) which must precede any carbon dioxide liberation, and the conversion of this to hexose-1,6-diphosphate (Harden-Young ester), which ferments slowly. The maximum of hexose-6-phosphate concentration coincides with the maximum car-... 

Phosphoric esters are also present in the blood, and their hydrolysis by means of an enzyme, phosphatase, which has been found in the bones, is probably one step in the process of ossification. The properties of these esters have been largely determined by Robison and his collaborators.3... 

Full references to this work may be obtained from the Annual Reports of the Chemical Society, especially vol. xxvi, 235, 1929 also The Significance of Phosphoric Esters in Metabolism," R. Robison, Oxford Univ. Press, 1933. 

M12. Martland, M., and Robison, R., Possible significance of hexosephosphoric esters in ossification. Part VI. Phosphoric esters in blood plasma. Biochem. J. 20, 847-855 (1926). 

R13. Robison, R., and Soames, K. M., The possible significance of hexose phosphoric esters in ossification. Part II. The phosphoric esterase of ossifying cartilage. Biochem. J. 18, 740-754 (1924). 

Rey, J. G. 1895. Naunyn-Schmiedeberg s Arch, exptl. Pathol, u. Pharmakol. 36, 295-305. Robison, R. 1932. The Significance of Phosphoric Esters in Metabolism. New York University Press, New York. 

This ester was first prepared 209) by partial hydrolysis of D-fructose diphosphate and later isolated by Robison 210) from the hexose monophosphate fraction obtained by yeast juice fermentation. 

Although it has now been almost completely abandoned, Robison s alkaline phosphatase theory formulated in 1923, emphasizes some of the essential problems that must be solved by any satisfactory theory of mineralization. Robison noticed that sites of mineralization frequently contain an enzyme operating at high pH values which is capable of hydrolysing organic phosphate esters with the release of inorganic phosphate ions ... 

Glucose Monophosphates.—A crude monophosphate (Robison s ester) has been obtained by the action of yeast juice on glucose or fructose. It is a mixture of fructose monophosphate (Neuberg s ester) and glucopyranose-6-phosphoric acid (Embden s ester). The two esters have been separated by fractional crystallisation of their brucine salts. A glucopyranose-1-monophosphate (Cori s ester) is obtained by the action of phosphate on minced muscle. 

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