Cori-ester

It had been known from at least the time of Pasteur that the presence of sodium or potassium phosphate aided the progress of a yeast fermentation. Later intensive study showed that a complex group of enzymes (phosphatases and phosphorylases) was responsible for the phosphorylation, dephosphorylation and interconversion of D-glucose 6-phosphate, D-fructose 6-phosphate, D-fructose 1,6-diphosphate and similar substances in various types of cells and muscle tissue. Detailed reviews of the field are available. - A further advance was made in 1936, when Cori and Cori noted that in certain circumstances well-washed frog muscle immersed in a sodium phosphate buffer utilized the inorganic phosphate to produce a new hexose phosphate (the Cori ester). This compound was later shown to be a-D-glucopyranose-l-phosphate and yielded crystalline dipotassium and brucine salts. The Cori ester arose because... 

Cori ester + D-fructose sucrose + inorganic phosphate,... 

Cori ester. See also n-Glucose-l-phos-phate. 

Cori ester, III, 258, 264 IV, 31 Com cobs, optical rotation of xylan from, V, 282... 

In this connection it may be mentioned that many ordinary yeasts ferment, generally very slowly, isomaltose and trisaccharides (limit dextrins) with one maltose and one isomaltose linkage. - Dried yeasts ferment starch and limit dextrins mth a fairly high velocity. This fermentation is probably not due to a hydrolysis of the saccharides to D-glucose or maltose, but to a phosphorolysis to the Cori ester (a-D-glucopyranose 1-phosphate). 

It appears that phosphorus is related to the formation of starch in the plant. Thus Hanes has synthesized a linear polysaccharide from a-D-glucopyranosc 1-phosphate (Cori ester) through the action of potato phosphorylase. Dunlap and Beckmann and likewise Cori have found that the B-fraction activates this enzymic synthesis, while the A-frac-tion is inactive. It has not been established whether this effect is due to the branched character of the B-fraction or to the presence of phosphate in its structure. 

In 1936 they discovered the previously unknown metabolic intermediate glucose-1-phosphate, known as the Cori ester. (See Figure 1). 

Incidental to the studies on cellulose nitrate, specifically C-la-beled cotton celluloses were prepared biologically, and some insight into biosynthesis in the cotton boll was obtained. a-D-Glu-copyranosyl phosphate, the anomer of the Cori ester, was synthesized, and a synthetic route to L-iduronic acid was devised both of these products were subsequently found by others to occur naturally. 

For the cellulose synthesis, guanosine diphosphate probably occurs in place of UDP. Adenosine triphosphate or Cori ester is also used for in vitro... 

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