Question

Catalysis by the enzyme glyceraldehyde 3‑phosphate dehydrogenase does NOT involve

a.) a covalent intermediate.
b.) an active site histidine to serve as a proton acceptor.
c.) phosphorylation of the substrate using ATP.
d.) oxidation and phosphorylation of the substrate.

Answer 1

The enzyme glyceraldehyde-3-phosphate dehydrogenase catalyzes the oxidation and phosphorylation of glyceraldehyde-3-phosphate, but does not involve a covalent intermediate or use an active site histidine as a proton acceptor.

Step-by-step explanation:

The enzyme glyceraldehyde-3-phosphate dehydrogenase catalyzes the oxidation of glyceraldehyde-3-phosphate by transferring high-energy electrons to NAD+ to produce NADH. This oxidation reaction does not involve a covalent intermediate.

The enzyme does not use an active site histidine to serve as a proton acceptor. Instead, during the reaction, a hydrogen molecule is split into a hydride ion (H-) and a proton (H+), and the H- ions reduce NAD+ to NADH.

The reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase does involve oxidation and phosphorylation of the substrate, as glyceraldehyde-3-phosphate is oxidized and phosphorylated to produce 1,3-bisphosphoglycerate.