Complex sentence: Thus, apolipoproteins are the protein constituents of lipoproteins, which also consist of phospholipids, triacylglycerols, cholesterol, and cholesterol esters.
Split into simpler sentences: Thus, apolipoproteins are the protein constituents of lipoproteins, which are particles combining lipids and proteins. The lipid component of lipoproteins consists of phospholipids, triacylglycerols, cholesterol, and cholesterol esters.