OxidationHHOHHBromino water.nitric acid------------------------------- ----------------------------HOCCOOHH C OHC OHHHO C HC HHOH C OHC OHHH C OHC OHHCH OH 2CH OH 2COOHC OHC HC OHC OHCOOHGluconic acidGlucoseGlucaric acid
Reduction Carbonyl groups can be reduced to alcohols (catalytichydrogenation)H O H[H]HRROH Sweet but slowly absorbed Glucose is reduced to sorbitol (glucitol) Xylose can be reduced to xylitol Once reduced – less reactive; not absorbed
Aldehyde sugars (reducing sugars) are readily oxidizedand will react with Benedict’s reagent.H|O -C=O| + 2 Cu 2+ + 5 OH -H-C-OH|CH 2 OH|C=O| + 2 Cu 2 O + 3H 2 OH-C-OH|CH 2 OH This provides a good test for presence ofglucose in urine -forms a red precipitate. Other tests - Tollen’s or Fehling’s solutions.
0.5% 2%glucos eB enedict'sReagent
or -OH group of cyclic monosaccharide can form linkwith another one (or more). glycosidic bondsugar -O- sugarHOHCH 2 OHHOHHOHOHOHHHOHOHOHCH 2 OHHHOHOHHCH 2 OHoxygen bridgeHOHCH 2 OHHOHHOHOHHoH OHOH+ H 2 OHOHHHOH
Type is based on the position of the C-1 OH glycosidic bond- linkage between a C-1 OH and a C-4 OH glycosidic bond- linkage between a C-1 OH and a C-4 OH bonds bondsOOOOC-4 end can be either up or down dependingon the orientation of the monosaccharide.
The replacement of a hydroxyl group on a carbohydrateresults in an amino sugar.CH 2 OHCH 2 OHHOHHOHOHOHHHOHHOHOHOHHHOHHNH 2-D-glucose-D-2-aminoglucose(glucosamine)
Uses for amino sugars. Structural components of bacterial cell walls. A major structural unit of chondroitin sulfate - acomponent of cartilage. Component of glycoprotein and glycolipids.