You are studying the enzyme alcohol dehydrogenase that catalyzes the following r

Question

You are studying the enzyme alcohol dehydrogenase that catalyzes the following reaction: NAD+ + ethanol ? NADH + H+ + acetaldehyde A) You discover that mercury ion (Hg+) at a concentration of 1 mM inhibits the enzyme by 95%. You find by appropriate kinetic experiments that the enzyme's apparent Km for ethanol is the same in the presence and the absence of Hg+. What does this tell you about the kind of inhibition caused by Hg+? B) Explain how you, as a working biochemist, might discover whether or not this enzyme is allosterically regulated.

Explanation / Answer

Alcohol dehydrogenases (ADH) (EC 1.1.1.1) are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+ to NADH). In humans and many other animals, they serve to break down alcohols that otherwise are toxic, and they also participate in generation of useful aldehyde, ketone, or alcohol groups during biosynthesis of various metabolites. In yeast, plants, and many bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply ogf NAD+ Binding of the coenzyme NAD+; Binding of the alcohol substrate by coordination to zinc; Deprotonation of His-51; Deprotonation of nicotinamide ribose; Deprotonation of Ser-48; Deprotonation of the alcohol; Hydride transfer from the alkoxide ion to NAD+, leading to NADH and a zinc bound aldehyde or ketone; Release of the product aldehyde;

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.