Question

What is special about hepatic lipase? Does it cleave TAG, or phospholipids, or both? Does it contain a ligand-binding action with SR-B1?

a) Cleaves TAG and phospholipids; No ligand-binding action with SR-B1
b) Cleaves TAG only; Ligand-binding action with SR-B1
c) Cleaves phospholipids only; Ligand-binding action with SR-B1
d) Cleaves both TAG and phospholipids; Ligand-binding action with SR-B1

Answer 1

Hepatic lipase has the ability to cleave both triglycerides and phospholipids and is involved in ligand-binding action with SR-B1, assisting in lipid uptake by cells.

Step-by-step explanation:

Hepatic lipase is an enzyme that plays a crucial role in lipid metabolism, specifically in the liver. It has the unique characteristic of not only cleaving triglycerides (TAG) but also phospholipids, aiding in the conversion of these molecules into more soluble end products like monoacylglycerols, diacylglycerols, and free fatty acids, which can then be utilized by the body. Additionally, hepatic lipase is known to interact with the scavenger receptor class B type 1 (SR-B1), a protein that facilitates the selective uptake of lipids, particularly cholesterol, into cells. This ligand-binding action allows hepatic lipase to contribute to the modulation of lipid levels within the bloodstream and tissues. Therefore, the appropriate choice that describes the actions of hepatic lipase would be 'cleaves both TAG and phospholipids; Ligand-binding action with SR-B1'.