Editing Lipoprotein (section)

{{Short description|Biochemical assembly for transporting hydrophobic lipid molecules}}
{{also|Proteolipid|Lipid-anchored protein}}
[[Image:Chylomicron.svg|thumb|250px|Structure of a [[chylomicron]] (the largest lipoprotein).<br />
'''[[Apolipoprotein AI|ApoA]]''', '''[[Apolipoprotein B|ApoB]]''', '''[[Apolipoprotein C|ApoC]]''', '''[[Apolipoprotein E|ApoE]]''' are [[apolipoprotein]]s; green particles are [[phospholipid]]s; '''T''' is [[triglyceride]]; '''C''' is [[cholesterol ester]].]]

A '''lipoprotein''' is a [[biochemical]] assembly whose primary function is to transport [[hydrophobic]] [[lipid]] (also known as [[fat]]) molecules in water, as in [[blood plasma]] or other [[extracellular fluid]]s. They consist of a [[triglyceride]] and [[cholesterol]] center, surrounded by a [[phospholipid]] outer shell, with the [[hydrophilic]] portions oriented outward toward the surrounding water and [[lipophilic]] portions oriented inward toward the lipid center. A special kind of protein, called [[apolipoprotein]], is embedded in the outer shell, both stabilising the complex and giving it a functional identity that determines its role.

'''Plasma lipoprotein particles''' are commonly divided into five main classes, based on size, lipid composition, and apolipoprotein content. They are, in increasing size order: [[High-density lipoprotein|HDL]], [[Low-density lipoprotein|LDL]], [[Intermediate-density lipoprotein|IDL]], [[Very-low-density lipoprotein|VLDL]] and [[chylomicron]]s. Subgroups of these plasma particles are primary drivers or modulators of [[atherosclerosis]].<ref>{{cite journal | vauthors = Gofman JW, Jones HB, Lindgren FT, Lyon TP, Elliott HA, Strisower B | title = Blood lipids and human atherosclerosis | journal = Circulation | volume = 2 | issue = 2 | pages = 161–78 | date = August 1950 | pmid = 15427204 | doi = 10.1161/01.CIR.2.2.161 | doi-access = free }}</ref>

Many [[enzyme]]s, [[Membrane transport protein|transporters]], structural proteins, [[antigen]]s, [[Adhesin molecule (immunoglobulin -like)|adhesin]]s, and [[toxin]]s are sometimes also classified as lipoproteins, since they are formed by lipids and proteins.