This molecule is cleaved from its C-4 epimer, glucose, by beta-gal.
A dimer of this molecule present in lone star tick bites leads to a peculiar allergy to red meat. One enzyme that hydrolyzes this molecule is only active at pH 6 and can be used as a marker for senescence. Brand and Perrimon developed a method that uses the upstream activation sequence controlling this compound's metabolism for targeted gene expression in Drosophila. A defect in the metabolism of this compound caused by mutations in the GALT gene can lead to (*) cataracts in infants.  An enzyme that removes this molecule from Gb3 is deficient in Fabry's disease. A blue color is produced when this molecule is cleaved from an indole chromophore in blue-white screens. This molecule is found on the ends of the O and B antigens, while its N-acetyl derivative is on the A. This molecule is cleaved from its C-4 epimer, glucose, by beta-gal. For 10 points, name this monosaccharide found with glucose in lactose.
A dimer of this molecule present in lone star tick bites leads to a peculiar allergy to red meat.
Galactose