You have discovered an enzyme that appears to function only when a particular sugar accumulates. Which of the following scenarios would you predict to be responsible for activating this enzyme? a. The sugar cleaves the enzyme to form the active conformation. b. The sugar is an allosteric regulatory molecule for the enzyme. c. The sugar is a competitive inhibitor for the enzyme. d. The sugar phosphorylates the enzyme to form the active conformation

Video transcript

Hi everyone. Here's our next problem. It says oxygen acts as an a list eric regulator of blank. Well, first, let's recall from our content videos, what is an a lost eric regulator. Well, this is a molecule that binds to an al ist eric site on a protein or enzyme causing a confirmation all change in that protein or enzyme. And that leads to activating or deactivating that protein or enzyme. And it's important to note when we think about this a list erIC site in an enzyme. This is not the active site. So this is not where you have the substrate binding um to allow the reaction to take place is a separate site on enzyme if it occurs on an enzyme. So, we'd have imagine our enzyme here and here is our active site where our substrate is going to come in and bind. Well, the palest eric site is going to be a separate site elsewhere. And when our Alice Terek regulator comes along and violence, a change is going to occur to this. So perhaps the active site will change in configuration. So maybe now that we have our little regulator in here, Maybe our active site will have a change in shape. Now can no longer bind the substrate and therefore that turns off its activity. But again, it's there's a separate site. If it's an enzyme, it's not the active site where this Alice Stark factor comes in causes a change in confirmation the protein affecting its activity. So oxygen is analyst eric regulator of hemoglobin. And this is because when a molecule of oxygen binds to one of the sub units of hemoglobin, this causes confirmation all changes in other subjects. Those changes increase their affinity for oxygen and therefore caused them to bind oxygen more efficiently. So even though oxygen is what's binding to all these subunits, oxygen in this case is also acting as an analyst eric regulator because it's binding to one subunit causes conformational changes in the other subunits. So just like we saw in this example of an enzyme with analyst erIC site um it's not the oxygen interacting with the oxygen binding sites, it's in a different site in the protein causing confirmation all changes. So our correct answer that we're looking for here is choice C hemoglobin as the molecule that oxygen acts as analyst eric regulator for so choice C hemoglobin is our correct answer. See you in the next video.