You are studying metabolic pathways and discover that two pathways intersect so that the enzyme basinase participates in both of the intersecting pathways, in one case using substrate K and in the other using substrate M. When presented with substrate K in amounts significantly larger than M, basinase converts K to L which leads eventually to the production of the end product R. The activity of the second pathway is depressed simultaneously. In the presence of large amounts of substrate M and lower amounts of substrate K, the second pathway is activated and culminates in the production of that pathway's end product Y. The activity of the first pathway is depressed simultaneously. What are the alternative substrates K and M acting like?

Question

Quizplus · Accepted Answer

Substrates K and M are acting as competitive inhibitors, as they are competing for the same enzyme (basinase) and binding to the same active site. When one substrate is present in excess, it out-competes the other for the active site, leading to a decrease in activity of the other pathway.

You Are Studying Metabolic Pathways and Discover That Two Pathways