Inhibition Ketose

Rare sugars have been reported to have healthful properties [1]. o-Psicose, a ketose sugar, has been shown to inhibit intestinal sucrase and maltase and suppress plasma glucose increase after sucrose and maltose ingestion in rats [11]. o-Allose has been reported to improve blood flow in the liver [12] and inhibit cancer cell proliferation [13],... 

D-Xylose isomerase catalyzes the reversible conversion of D-xylose into D-xylulose, and it is also capable of converting other sugars from aldose into ketose. The enzyme requires Co +, or Mn " " for activation while zinc and calcium dications inhibit cataiysis. Crystaiiographic data indicate... 

There is an obvious reluctance of carbohydrates to crystallize in a form suitable for X-ray or neutron diffraction studies. This is particularly true for aldose and ketose containing carbohydrates as a configurational mixture of four isomers, a-and P-pyranoses and a- and P-furanose, is likely to occur. Configurational heterogeneity in solution tends to inhibit crystallization. For this reason 1-O-methyl derivatives, which cannot epimerize, are likely to crystallize more readily. In some instances, the a and P epimers can co-crystallize, and more than 10 examples of such co-crystallization can be found. The a and p ratio may be dependent on the temperature and solvent of crystallization, and may not be reproducible between independent investigators. One extreme example is provide by the crystal struc-... 

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