from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of various carbohydrates containing a ketone group.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A saccharide containing a ketone functional group.
from The Century Dictionary and Cyclopedia
- n. A class-name applied in organic chemistry to sugars, such as fructose, containing a ketone group.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any monosaccharide sugar that contains a ketone group or its hemiacetal
Sorry, no etymologies found.
I had been looking for evidence of proton transfer in enzymes that catalyzed aldose-ketose interconversions.
As shown in Table 1, isomerases that are specific for 2R-aldoses were found to activate the 1-R proton of the ketose produced.
If now the aldose groups tend to pass over into the starch form, representing a temporary overflow product of the assimilating energy, it would appear that the ketose or levulose groups are preferentially used up in the elaboration of the permanent tissue.
The reason it is a 4 membered ring is because it is a ketose, as opposed to an aldose.