| cholesterol | 1. <biochemistry> A pearly, fatlike steroid alcohol, C27H45OH, crystallizing in the form of leaflets or plates from dilute alcohol and found in animal fats and oils, in bile, blood, brain tissue, milk, yolk of egg, myelin sheaths of nerve fibres, the liver, kidneys and adrenal glands. It constitutes a large part of the most frequently occurring type of gallstones and occurs in atheroma of the arteries, in various cysts and in carcinomatous tissue. Most of the bodys cholesterol is synthesised in the liver, but some is absorbed from the diet. It is a precursor of bile acids and is important in the synthesis of steroid hormones. 2. <chemical> A commercial preparation of cholesterol is used as a pharmaceutic aid. Synonym: cholesterin. Origin: Gr. Stereos = solid (15 Jan 1998) |
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| cholesterol 26-hydroxylase | <enzyme> Cyt p-450 dependent, ferredoxin involved Registry number: EC 1.14.15.- (26 Jun 1999) |
| cholesterol 7 alpha-monooxygenase | <enzyme> An enzyme that catalyses the hydroxylation of cholesterol to cholest-5-en-3 beta,7 alpha-diol. Chemical name: Cholesterol,NADPH:oxygen oxidoreductase (7 alpha-hydroxylating) Registry number: EC 1.14.13.17 (12 Dec 1998) |
| cholesterol cleft | A space caused by the dissolving out of cholesterol crystals in sections of tissue embedded in paraffin. (05 Mar 2000) |
| cholesterol dehydrogenase | <enzyme> Converts cholesterol to coprostanol; mechanism given is incorrect for enzyme name Registry number: EC 1.3.- (26 Jun 1999) |
| cholesterol embolism | Embolism of lipid debris from an ulcerated atheromatous deposit, generally from a large artery to small arterial branches; it is usually small and rarely causes infarction. Synonym: atheroma embolism. (05 Mar 2000) |
| cholesterol ester storage disease | A rare benign adult form of inherited lysosomal lipid storage disease that is due to deficiency of acid lipase. It results in an accumulation of neutral lipids, particularly cholesterol esters, within cells (particularly leukocytes, fibroblasts, and liver cells). It is an allelic variant of wolman disease. (12 Dec 1998) |
| cholesterol ester transport proteins | A protein that transports cholesterol esters from HDL to VLDL and LDL; a deficiency of this protein is associated with elevated HDL cholesterol. (05 Mar 2000) |
| cholesterol esterase | <enzyme> An enzyme that catalyses the hydrolysis of cholesterol and some other sterol esters, to liberate cholesterol plus a fatty acid anion. Chemical name: Steryl-ester acylhydrolase Registry number: EC 3.1.1.13 (12 Dec 1998) |
| cholesterol esters | Fatty acid esters of cholesterol which constitute about two-thirds of the cholesterol in the plasma. The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis. (12 Dec 1998) |
| cholesterol monooxygenase | <enzyme> Multi-enzyme complex required for the conversion of cholesterol to adrenal cortex hormones. It releases methylpentanoate or isocaproaldehyde and pregnenolone. The complex contains cytochrome p-450, a flavoprotein, a non-haem iron protein, and NADPH. Chemical name: Cholesterol,reduced-adrenal-ferredoxin:oxygen oxidoreductase (side-chain-cleaving) Registry number: EC 1.14.15.6 (12 Dec 1998) |
| cholesterol oxidase | <enzyme> An enzyme that catalyses the oxidation of cholesterol in the presence of molecular oxygen to 4-cholesten-3-one and hydrogen peroxide. The enzyme is not specific for cholesterol, but will also oxidise other 3-hydroxysteroids. Chemical name: Cholesterol:oxygen oxidoreductase Registry number: EC 1.1.3.6 (12 Dec 1998) |
| cholesterol reductase | <enzyme> Uses NADH; reduces cholesterol to cholestanol (coprostanol) Registry number: EC 1.3.1.- (26 Jun 1999) |
| cholesterol sulfotransferase | <enzyme> Transfers sulfate from paps to cholesterol Registry number: EC 2.8.2.- (26 Jun 1999) |
| cholesterol, bad | Low-density lipoprotein (LDL) cholesterol. (12 Dec 1998) |
| acid cholesterol ester synthetase | <enzyme> Aortal enzyme, does not require exogenous ATP or CoA; reverse reaction of cholesterol esterase Registry number: EC 3.1.1.- Synonym: cholesterol ester synthetase (26 Jun 1999) |
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| good cholesterol | High-density lipoprotein (HDL) cholesterol. (12 Dec 1998) |
| hdl cholesterol | High-density lipoprotein cholesterol (the good cholesterol). (12 Dec 1998) |
| high blood cholesterol | A condition where there is an above normal level of cholesterol in the bloodstream. A level of over 200 mg/dl is known to be a risk factor for heart disease. Less than 200 is desirable, 200 to 239 is considered borderline high, over 240 is considered high. (27 Sep 1997) |
| NAD(P)+-dependent cholesterol dehydrogenase | <enzyme> Oxidises the 3 beta-oh group of cholesterol to cholestenone in the presence of NADP+ Registry number: EC 1.1.1.- Synonym: NADP+-dc-dehydrogenase, cholesterol 3-dehydrogenase (26 Jun 1999) |
| i-cholesterol isomerase | <enzyme> 7-hydroxy group is isomerised to position 3 on ring a to form cholesterol Registry number: EC 5.4.99.- (26 Jun 1999) |
| embolism, cholesterol | An embolism of lipid debris from an ulcerated atheromatous deposit, generally from a large artery to small arterial branches. It is usually small and rarely causes infarction. (12 Dec 1998) |
| total cholesterol | A combination of the LDL, HDL and VLDL levels in the bloodstream. This is the cholesterol measurement that is given by the standard home cholesterol test kit. Less than 200 is desirable, 200 to 239 is considered borderline high, over 240 is considered high. (27 Sep 1997) |
| ldl cholesterol | Low-density lipoprotein cholesterol (the bad cholesterol). (12 Dec 1998) |
| lecithin-cholesterol acyltransferase | <enzyme> An enzyme that reversibly transfers an acyl residue from a lecithin to cholesterol, forming a 1-acylglycerophosphocholine (a lysolecithin) and a cholesterol ester; a deficiency of this enzyme leads to an accumulation of unesterified cholesterol in plasma resulting in anaemia, proteinuria, renal failure, and corneal opacities; LCAT is also low in individuals with fish-eye disease. Synonym: lecithin acyltransferase. Acronym: LCAT (05 Mar 2000) |
| lecithin-cholesterol transferase | A plasma enzyme that catalyses the uptake of cholesterol esters by intermediate-density lipoproteins formed by high density lipoproteins. (05 Mar 2000) |
| lipoproteins, hdl cholesterol | Cholesterol which is contained in or bound to high density lipoproteins (hdl). High density lipoproteins transport cholesterol from peripheral tissues to the liver thereby acting as a scavenger to prevent excess accumulation and deposition of cholesterol in blood vessels. (12 Dec 1998) |
| lipoproteins, ldl cholesterol | Cholesterol which is contained in or bound to low density lipoproteins (ldl). Ldl transport cholesterol to peripheral tissues and regulate de novo cholesterol synthesis at these sites. Atherosclerosis is caused by the deposit of cholesterol on the walls of blood vessels, because of high concentrations of ldl cholesterol in plasma. (12 Dec 1998) |
| lipoproteins, vldl cholesterol | Cholesterol which is contained in or bound to very low density lipoproteins (vldl). High concentrations of vldl cholesterol are found in type IIb and type v hyperlipoproteinaemia. The end product of vldl cholesterol catabolism is ldl (low density lipoproteins). (12 Dec 1998) |