Question

Ethylene glycol is an ingredient in antifreeze. If antifreeze is swallowed, the enzyme alcohol dehydrogenase binds to the ethylene glycol and converts it to tacowalic and glycolic acid. One of the treatments for ethylene glycol poisoning is the administration of the enzyme's natural substrate, ethanol. Based on this information, what is the best way to describe how ethanol protects against ethylene glycol poisoning? View Available Hints) Ethanol competes with ethylene glycol to limit akalic and glycolic acid formation Ethanol serves as a feedback inhibitor to limit ethylene glycol interaction with the enzyme's active site Ethanol alosterically inhibits the production of oxalic and glycolic acids. Ethanol acts as a non-competitive inhibitor to block oxalic and glycolic acid formation Submit

Answer 1

As ethanol is a natural substrate for the enzyme alcohol dehydrogenase. If administered, it occupies the enzyme active site and increases the competition for ethylene glycol and minimizes the formation of toxic intermediates produced by the catalysis of ethylene glycol. Thus, ethanol acts as a competitive inhibitor for ethylene glycol.

So, option 1 is correct.

Ethanol gets converted to acetaldehyde which later gets converted to acetic acid by another enzyme acetaldehyde dehydrogenase. In the end, acetic acid is converted to carbon dioxide and water. Thus toxicity due to oxalic acid and glycolytic acid is reduced by their decreased production.

Feedback inhibition is the process by which one of the products of enzyme-catalyzed reaction binds to the enzyme and inhibits its activity. In the above case, the enzyme is not inhibited infant different substrate is added which competes for the enzymes active site. Allosteric regulation is the phenomenon by which a ligand binds to the enzyme's specific site (allosteric site) unrelated to the active site and leads to conformational changes in the enzyme. Thus, other options are not correct.