galactose

Galactose -- C₆H₁₂OH

An optical isomer of the famous Glucose which is different from it at the fourth Carbon (Its OH group is perpendicular* to the ring instead of being equatorial* as in the glucose).

Galactose's Fischer* drawings:

  L-Gal:       D-Gal:
   C1-HO        C1-HO
OH-C2-H       H-C2-OH
 H-C3-OH     OH-C3-H
 H-C4-OH     OH-C4-H
OH-C5-H       H-C5-OH
   C6-H2OH      C6-H2OH

Galactose's Mills diagram: (Look at ma', I'm an ASCII artist!)

             /
          C /
            \
             \
              ------O
             /       \
            /         \
    -------<           >-------
            \         /
             \       /
              -------
             /       \
            /
           /           \
          /             
         /               \

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.

Ga*lac"tose (?), n. Chem.

A white, crystalline sugar, C6H12O6, isomeric with dextrose, obtained by the decomposition of milk sugar, and also from certain gums. When oxidized it forms mucic acid. Called also lactose (though it is not lactose proper).

© Webster 1913.