Terminology

ACP (Acyl-Carrier Protein) - acyl carrier group used in fatty acid biosynthesis (Figure 18.26)
Adipocytes - Cells of the body involved in storage of fat.
Adipose Tissue - body tissue in animals where fat is stored.
Albumin - protein that carries fatty acids in the bloodstream.
Oxidation - term used to describe the a minor oxidative pathway of fatty acid metabolism. Name comes from the fact that oxidation begins one carbons behind the carboxyl moiety (Figure 18.20).
Apo aI - a peptide of molecular weight 28,300 that is a major component of HDLs. It activates the enzyme, LCAT. It is also found in chylomicrons (Table 18.2).
Apo aII - a polypeptide of molecular weight 17,400 that is a major component of HDLs. It is also found in chylomicrons (Table 18.2).
Apo b100 - the major protein found in LDLs and a lesser constituent of IDLs and VLDLs (Table 18.2).
Apo b48 - a protein of molecular weight 241,000 found exclusively in chylomicrons. Coding for it derives from the N-terminal region of Apo B-100 (Table 18.2).
Apo cI - a small polypeptide of 7,000 molecular weight found in chylomicrons. It functions to activate LCAT and Lipoprotein Lipase(Table 18.2).
Apo cII - a polypeptide of molecular weight 10,000 found primarily in VLDLs and, to a lesser extent, in chylomicrons. It functions to activate Lipoprotein Lipase. A human deficiency of this polypeptide is associated with elevated triacylglycerol levels in blood (Table 18.2).
Apo cIII - a polypeptide of molecular weight 9,300 found primarily in chylomicrons, VLDLs, and HDLs. It inhibits the action of Lipoprotein Lipase (Table 18.2).
Apo D - a polypeptide found in HDLs. It is also called cholesterol ester transfer protein (Table 18.2).
Apo E - a protein found in VLDLs, LDLs, and HDLs. With a molecular weight of 33,000. Is involved in binding lipoprotein complexes to the LDL receptor. Is found in the human Apo C-II gene cluster and a variant of this protein has been associated with an increased risk for Alzheimer's disease (Table 18.2).
Apolipoproteins - protein components of lipoprotein complexes.
Atherogenesis - the process of plaque formation in arteries.
Bad Cholesterol - term used to describe the LDLs based on the fact that high levels of them are linked to atherosclerosis.
Oxidation - term used to describe the primary oxidative pathway of fatty acid metabolism. Name comes from the fact that oxidation begins two carbons behind the carboxyl moiety.
Bile Salts - Detergent-like substances secreted by the gall bladder. They are derived from cholesterol and help to emusify fat after a meal (Figure 18.4)
Biotin - a vitamin and a coenzyme commonly associated with enzymes performing carboxylation reactions.
Chylomicrons - lipoprotein complexes that carry dietary lipids (including cholesterol) from the lymph through the bloodstream (Table 18.1, Figure 18.7).
Citrate Shuttle - System that operates between the mitochondria and the cytoplasm to move acetyl-CoA out to the cytoplasm for fatty acid synthesis (Figure 18.21).
Coated Pit - receptor in the cell membrane that participate in the process of receptor mediated endocytosis.
Clathrin - the most abundant protein found in coated pits, the site of LDL receptors, which participate in receptor-mediated endocytosis.
Endocytosis - a process by which cells take up large molecules from the extracellular environment (Figure 18.10).
Endosome - in receptor mediated endocytosis, name for several of the clathrin-lined vesicles that fuse after absorption into a cell (Figure 18.10).

Foam Cells - Cholesterol-engorged immune cells implicated in formation of atherosclerotic plaques.
Good Cholesterol - term used to describe HDLs based on the fact that high levels of them counteract atherogenesis.
HDL (high-density lipoproteins) - lipoprotein complexes often referred to as the "good cholesterol" because they function to take cholesterol from peripheral tissues back to the liver and help lower total serum cholesterol (Table 18.1, Figure 18.7).
IDL (intermediate density lipoproteins) - lipoprotein complexes that carry lipids in the bloodstream. Are derived from VLDLs and can be converted into LDLs (Table 18.1, Figure 18.7).
Insulin - a peptide hormone that functions in lowering of blood glucose levels. Counteracts the effects of glucagon and epinephrine by favoring dephosphorylation of the proteins that are phosphorylated by the kinase cascade.
Ketogenesis - refers to the process of forming ketone bodies.

Ketone Bodies - Molecules produced by the process of ketogenesis, which occurs when acetyl-CoA accumulates beyond its capacity to be oxidized or used for fatty acid synthesis. Examples include acetoacetate, acetone, and -hydroxybutyrate. (Figure 18.21).
LDL (low density lipoproteins) - lipoprotein complexes referred to as "bad cholesterol" because prolonged elevation of levels of these leads to atherosclerosis. Are the primary transport vehicle for cholesterol synthesized in the liver (Table 18.1, Figure 18.7).
Leptin - the product of the "ob" gene, originally identified in abnormally obese mice. The gene acts as a hormone, binding to a specific site in the brain.
-3 Fatty Acids - Fatty acids found in relatively high amounts in fish oils compared to red meats. They tend to depress levels of both serum cholesterol and triacylglycerols.
Phytanic Acid - an unusual fatty acid derived from phytol which accumulates in patients with Refsum's disease (Figure 18.20).
Polyketides - a class of antibiotics which are made in pathways like fatty acid biosynthesis, but in which one or more of the activities are missing. Examples include erythromycin and oxytetracycline (Figure 18.35).
Scavenger Receptor - a specialized receptor on the surface of white blood cells that binds to oxidized LDLs in the process of engorging the LDL.
VLDL (very low density lipoproteins) - lipoprotein complexes that carry lipids in the bloodstream. Precursors of IDLs (Table 18.1, Figure 18.7).