Final answer:
Inhibition by compounds like unphosphorylated EIIAGlc in the presence of high glucose can regulate lactose digestion by preventing the transport of lactose into the cell, thus controlling the amount of lactose hydrolyzed.
Step-by-step explanation:
The inhibition caused by a compound in the digestive tract can regulate the amount of lactose hydrolyzed by influencing the activity of enzymes involved in lactose digestion. This type of regulation is exemplified in the lac operon of E. coli, which provides a mechanism to preferentially use glucose over lactose when both sugars are available.
High levels of glucose lead to a low concentration of cytoplasmic phosphate, causing EIIAGlc to remain unphosphorylated. Unphosphorylated EIIAGlc binds to lactose permease, preventing it from importing lactose into the cell, and thus reducing the amount of lactose hydrolyzed. Conversely, when glucose is scarce, phosphate levels rise, leading to the phosphorylation of EIIAGlc.
Phosphorylated EIIAGlc dissociates from lactose permease, allowing lactose entry and subsequent hydrolysis. This process, known as inducer exclusion, is a way to regulate lactose intake based on the presence of glucose, and ensures optimal energy usage by the cell.