Target type: molecularfunction
Catalysis of the reaction: acyl-CoA + cholesterol = a cholesterol ester + CoA. [EC:2.3.1.26, RHEA:17729]
Cholesterol O-acyltransferase (ACAT) activity is a crucial enzymatic process responsible for the esterification of cholesterol. This reaction involves the attachment of a fatty acid to the hydroxyl group of cholesterol, forming cholesteryl esters. ACAT primarily plays a role in regulating cellular cholesterol levels and maintaining lipid homeostasis.
The ACAT enzyme catalyzes the transfer of a fatty acyl group from a donor molecule, such as acyl-CoA, to the 3-hydroxyl group of cholesterol. This process results in the formation of cholesteryl esters, which are less soluble in water and are stored in lipid droplets within cells.
There are two main isoforms of ACAT: ACAT1 and ACAT2. ACAT1 is primarily expressed in the liver and is responsible for the majority of cholesteryl ester synthesis. ACAT2 is expressed in various tissues, including the intestines, adrenal glands, and macrophages.
The molecular function of ACAT activity is essential for several physiological processes, including:
- **Cholesterol homeostasis:** ACAT activity regulates cellular cholesterol levels by converting free cholesterol to cholesteryl esters, which can be stored in lipid droplets. This process prevents cholesterol accumulation in cell membranes and maintains lipid balance.
- **Lipid transport:** Cholesteryl esters synthesized by ACAT can be packaged into lipoproteins, such as very low-density lipoproteins (VLDL), and transported to peripheral tissues.
- **Atherosclerosis:** Increased ACAT activity in macrophages can contribute to the development of atherosclerosis. This is because ACAT promotes the formation of foam cells, which are cholesterol-laden macrophages that accumulate in the arterial walls.
In summary, ACAT activity is a critical molecular process that plays a vital role in regulating cholesterol levels, lipid transport, and atherosclerosis. Its function is essential for maintaining lipid homeostasis and preventing disease.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Sterol O-acyltransferase 1 | A sterol O-acyltransferase 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P35610] | Homo sapiens (human) |
| Sterol O-acyltransferase 2 | A sterol O-acyltransferase 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O75908] | Homo sapiens (human) |
| Sterol O-acyltransferase 1 | A sterol O-acyltransferase 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P35610] | Homo sapiens (human) |
| Sterol O-acyltransferase 2 | A sterol O-acyltransferase 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:O75908] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| diethyl pyrocarbonate | diethyl pyrocarbonate : The diethyl ester of dicarbonic acid. Diethyl Pyrocarbonate: Preservative for wines, soft drinks, and fruit juices and a gentle esterifying agent. | acyclic carboxylic anhydride | |
| procainamide | procainamide : A benzamide that is 4-aminobenzamide substituted on the amide N by a 2-(diethylamino)ethyl group. It is a pharmaceutical antiarrhythmic agent used for the medical treatment of cardiac arrhythmias. Procainamide: A class Ia antiarrhythmic drug that is structurally-related to PROCAINE. | benzamides | anti-arrhythmia drug; platelet aggregation inhibitor; sodium channel blocker |
| edrophonium chloride | edrophonium chloride : The chloride salt of edrophonium. A reversible inhibitor of cholinesterase with a rapid onset (30-60 seconds after injection) but a short duration of action (5-15 minutes), it is used in myasthenia gravis both diagnostically and to distinguish between under- or over-treatment with other anticholinesterases. It has also been used for the reversal of neuromuscular blockade in anaesthesia, and for the management of poisoning due to tetrodotoxin, a neuromuscular blocking toxin found in puffer fish and other marine animals. | chloride salt; quaternary ammonium salt | antidote; diagnostic agent; EC 3.1.1.8 (cholinesterase) inhibitor |
| territrem b | territrem B: tremorgenic mycotoxin from Aspergillus terreus; RN given refers to (4aR-(4aalpha,6abeta,12aalpha,12bbeta))-isomer | ||
| pd 128042 | PD 128042: structure given in first source | anilide | |
| cl 277082 | CL 277082: structure given in first source | ||
| 1,4-bis(4-methoxyphenyl)-3-(3-phenylpropyl)-2-azetidinone | 1,4-bis(4-methoxyphenyl)-3-(3-phenylpropyl)-2-azetidinone: an inhibitor of cholesterol absorption; structure given in first source | ||
| atractylenolide iii | atractylenolide III: from Atractylodes macrocephala Koidz; structure in first source | naphthofuran | metabolite |
| avasimibe | monoterpenoid | ||
| 22s-hydroxycholesterol | (22S)-22-hydroxycholesterol : An oxysterol that is the 22S-hydroxy derivative of cholesterol. | 22-hydroxy steroid; 3beta-hydroxy-Delta(5)-steroid; oxysterol | |
| f 1394 | F 1394: an acyl-CoA:cholesterol acyltransferase (ACAT) inibitor; structure given in first source | ||
| oleic acid | oleic acid : An octadec-9-enoic acid in which the double bond at C-9 has Z (cis) stereochemistry. Oleic Acid: An unsaturated fatty acid that is the most widely distributed and abundant fatty acid in nature. It is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent. (Stedman, 26th ed) | octadec-9-enoic acid | antioxidant; Daphnia galeata metabolite; EC 3.1.1.1 (carboxylesterase) inhibitor; Escherichia coli metabolite; mouse metabolite; plant metabolite; solvent |
| beta-hydroxyisovalerylshikonin | |||
| shikonin | shikonin: a naphthazarin; has antineoplastic and angiogenesis inhibiting activities | hydroxy-1,4-naphthoquinone | |
| carbenoxolone | |||
| pactimibe | |||
| linoleic acid | linoleic acid : An octadecadienoic acid in which the two double bonds are at positions 9 and 12 and have Z (cis) stereochemistry. Linoleic Acid: A doubly unsaturated fatty acid, occurring widely in plant glycosides. It is an essential fatty acid in mammalian nutrition and is used in the biosynthesis of prostaglandins and cell membranes. (From Stedman, 26th ed) | octadecadienoic acid; omega-6 fatty acid | algal metabolite; Daphnia galeata metabolite; plant metabolite |
| oleylamide | aliphatic amide : A carboxamide in which the amide linkage is bonded directly to an aliphatic system. oleamide : A fatty amide derived from oleic acid. oleylamide: plastic additive; can cause contact urticaria; RN given refers to (Z)-isomer; a sleep inducing factor | primary fatty amide | human metabolite; plant metabolite |
| muromonab-cd3 | cudraflavone B : An extended flavonoid that consists of a pyranochromane skeleton that is 2H,6H-pyrano[3,2-g]chromen-6-one substituted by geminal methyl groups at position 2, a 2,4-dihydroxyphenyl group at position 8, a hydroxy group at position 5 and a prenyl group at position 7. Isolated from Morus alba and Morus species it exhibits anti-inflammatory activity. cudraflavone B: antiproliferative from Cudrania tricuspidata | extended flavonoid; pyranochromane; trihydroxyflavone | anti-inflammatory agent; plant metabolite |
| macluraxanthone b | macluraxanthone B : A member of the class of xanthones that is 9H-xanthen-9-one substituted by hydroxy groups at positions 1, 3, 6 and 7, a dimethylallyl group at position 2 and a prenyl group at position 4. Isolated from Maclura tinctoria and Cudrania tricuspidata, it exhibits anti-HIV and antineoplastic activity. macluraxanthone B: from the plant Maclura tinctoria; structure in first source | phenols; xanthones | anti-HIV agent; antineoplastic agent; metabolite |
| oleoylanilide | oleoylanilide: alters lipid metabolism of lung & adipose tissue; do not confuse with oleoanilide; RN given refers to (Z)-isomer oleylanilide : The fatty amide resulting from the formal condensation of oleic acid and aniline. | anilide; fatty amide | |
| Pipercide | benzodioxoles | ||
| linoleamide | linoleamide : A fatty amide obtained from linoleic acid. linoleamide: C18-H33-N-O | primary fatty amide | human metabolite |
| manzamine a | manzamine A : An alkaloid of the class of beta-carbolines isolated from Haliclona and Acanthostrongylophora. It exhibits inhibitory activity against Glycogen Synthase Kinase-3 (EC 2.7.11.26). manzamine A: RN given refers to (1R-(1R*,9Z,13S*,13aR*,20aR*,21aR*)-isomer; RN for cpd without isomeric designation not avail 12/92 | alkaloid; beta-carbolines; isoquinolines | animal metabolite; anti-HSV-1 agent; antimalarial; antineoplastic agent; EC 2.7.11.26 (tau-protein kinase) inhibitor; marine metabolite |
| eflucimibe | eflucimibe: a powerful and systemic acylcoenzyme A: cholesterol acyltransferase inhibitor | ||
| arisugacin | arisugacin A : An organic heterotetracyclic compound that is 4a,12a-dihydroxy-4,4,6a,12b-tetramethyl-4a,6,6a,12,12a,12b-hexahydro-4H,11H-benzo[f]pyrano[4,3-b]chromene-1,11(5H)-dione substituted by 3,4-dimethoxyphenyl group at position 9 (the 4aR,6aR,12aS,12bS steroisomer). Isolated from the culture broth of Penicillium, it acts as a selective inhibitor of acetylcholinesterase. arisugacin: isolated from Penicillium sp. FO-4259; structure given in first source | aromatic ether; delta-lactone; enone; organic heterotetracyclic compound; tertiary alcohol | antimicrobial agent; EC 3.1.1.7 (acetylcholinesterase) inhibitor; metabolite; Penicillium metabolite |
| manassantin b | manassantin B : A lignan isolated from Saururus cernuus and Saururus chinensis and has been shown to exhibit antineoplastic activity. manassantin B: isolated from the roots of Saururus chinensis; structure in first source | benzodioxoles; dimethoxybenzene; lignan; oxolanes; secondary alcohol | antineoplastic agent; metabolite |
| cudraxanthone l | cudraxanthone L: from the root bark of Cudrania tricuspidata; structure in first source | ||
| pyripyropene a | pyripyropene A : A sesquiterpenoid that consists of (3S,4R,4aR,6S,6aS,12R,12aS,12bS)-4-(acetoxymethyl)-12-hydroxy-4,6a,12b-trimethyl-11-oxo-9-(pyridin-3-yl)-1,3,4,4a,5,6,6a,12,12a,12b-decahydro-2H,11H-benzo[f]pyrano[4,3-b]chromene-3,6-diol in which the hydrogens of the 3- and 6-hydroxy functions are substituted by acetyl groups. pyripyropene A: from Aspergillus fumigatus FO-1289; structure given in first source | organic heterotetracyclic compound; sesquiterpenoid | acyl-CoA:cholesterol acyltransferase 2 inhibitor; metabolite |
| cudraflavanone a | cudraflavanone A: antineoplastic from Cudrania tricuspidata; structure in first source | ||
| azd7687 | AZD7687: structure in first source | ||
| manassantin a | manassantin A : A lignan isolated from Saururus cernuus and Saururus chinensis and has been shown to exhibit antineoplastic activity. manassantin A: a dineolignan from Saururus cernuus; structure in first source |