Abstract
ON solution in water, beta d-fructopyranose, the only crystalline form of d-fructose, exhibits mutarotation which mainly consists in a pyranose ⇌ furanose interconversion1,2. In experiments at 0° C. and pH. = 4·5, under which conditions mutarotation proceeds the slowest, it was previously3 shown that beta d-fructopyranose added to a suspension of baker's yeast in 0·1 M KH2PO4 is unfermentable, whereas alpha d-glucose is fermented at the expected rate. Since in any quantitative consideration of the composition of a d-fructose solution at equilibrium (pH. = 4·5) open-chain forms (keto-form, enol-form) can be neglected, d-fructofuranose, chiefly present in the beta configuration, remains as the only fermentable isomer. The non-fermentability of d-fructopyranose—obviously due to lack of an OH-group at C6—rendered possible the determination of the proportion of the furanose form in an equilibrium mixture of d-fructose at 0° C.; this proportion was found4 to be 12 per cent. From this figure and the known differences in mutarotation of d-fructopyranose at 0° C. and at 25° C., it can be calculated that an equilibrated d-fructose solution at 25° C. contains approximately 22 per cent of the sugar in the furanose modification; it is in this way that the concentrations of fructofuranose given in this report have been derived.
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Purves, C. B., and Hudson, C. S., J. Amer. Chem. Soc, 56, 702 (1934).
Isbell, H. S., and Pigman, W. W., J. Res. Nat. Bur. Standards, 20, 773 (1938).
Gottschalk, A., Austral J. Exp. Biol., 21, 133 (1943).
Gottschalk, A., Austral. J. Exp. Biol, 21, 139 (1943).
Hopkins, R. H., Biochem. J., 25, 245 (1931).
Gottschalk, A., Austral. J. Exp. Biol., 22, 291 (1944).
Sobotka, H., and Reimer, M., Biochem. J., 24, 1783 (1930).
Fernbach, A., Schoen, M., and Mori, M., Ann. Inst. Pasteur, 42, 805 (1928).
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GOTTSCHALK, A. Yeast Hexokinase and Its Substrates d-Fructofuranose and d-Glucose. Nature 156, 540–541 (1945). https://doi.org/10.1038/156540a0
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DOI: https://doi.org/10.1038/156540a0
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