Galactosemia caused by a transferase deficiency is characterized by elevated levels of galactose, galactitol, and galactose 1‑ph
osphate. Galactose and galactitol are precursors of galactose 1‑phosphate. Transferase deficiency studies in animal models suggest that galactose 1‑phosphate is the toxic agent. Which result from a galactosemia study in an animal model will implicate galactose 1‑phosphate as the toxic agent in a transferase deficiency? Inhibition of UDP‑glucose 4‑epimerase in affected animals prevents toxicity. Affected animals given a lactase inhibitor do not experience toxicity. Inhibition of galactose transporter in the intestinal cells prevents toxicity. Affected animals given a galactokinase inhibitor do not experience toxicity. A galactose‑free diet eliminates toxicity in affected animals.
Affected animals given a galactokinase inhibitor do not experience toxicity.
Explanation:
Galactokinase: Catalyzes is the first and committed step of the Leloir pathway involving the conversion of galactose to glucose. It causes phosphorylation of α-D-galactose to galactose 1‑phosphate. Thus, inhibiting galactokinase wil greatly decrease the levels of galactose 1‑phosphate.
Morris Goodman was a editor-in-chief of the journal Molecular Phylogenetics and Evolution.
In his classification, every organism was traced back to its last common ancestors, and he traced that of primates last common ancestors to be dated as far back as 63 MYA.
