Esterase

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An esterase is a hydrolase enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis.

A wide range of different esterases exist that differ in their substrate specificity, their protein structure, and their biological function.

[edit] EC classification/list of enzymes

Esterases are classified as EC 3.1 in the EC number classification of enzymes. They are further subclassified into:

• EC 3.1.1: Carboxylic ester hydrolases
  • Lipase (EC 3.1.1.3), splits fat and lipids into fatty acids and glycerol or other alcohols
    • Phospholipase (PL), hydrolyzes phospholipids
    • Lipoprotein lipase, hydrolyzes lipids in lipoproteins
    • Acid hydrolase (lysosomal acid lipase), found in lysozomes which are strongly acidic
  • Acetylesterase (EC 3.1.1.6), splits off acetyl groups
    • Cholinesterase
      • Acetylcholinesterase, inactivates the neurotransmitter acetylcholine
      • Pseudocholinesterase, broad substrate specificity, found in the blood plasma and in the liver
  • Pectinesterase (EC 3.1.1.11), clarifies fruit juices

• EC 3.1.2: Thiolester hydrolases
  • Thioesterase
    • Ubiquitin carboxy-terminal hydrolase L1

• EC 3.1.3: Phosphoric monoester hydrolases
  • Phosphatase (EC 3.1.3.x), hydrolyses phosphoric acid monoesters into a phosphate ion and an alcohol
    • Alkaline phosphatase, removes phosphate groups from many types of molecules, including nucleotides, proteins, and alkaloids.
    • Phosphodiesterase (PDE), inactivates the second messenger cAMP
      • cGMP specific phosphodiesterase type 5, is inhibited by Sildenafil (Viagra)
  • Fructose bisphosphatase (3.1.3.11), converts fructose-1,6-bisphosphate to fructose-6-phosphate in gluconeogenesis

• EC 3.1.4: Phosphoric diester hydrolases

• EC 3.1.5: Triphosphoric monoester hydrolases

• EC 3.1.6: Sulfuric ester hydrolases (sulfatases)

• EC 3.1.7: Diphosphoric monoester hydrolases

• EC 3.1.8: Phosphoric triester hydrolases

• Exonucleases (deoxyribonucleases and ribonucleases)
  • EC 3.1.11: Exodeoxyribonucleases producing 5'-phosphomonoesters
  • EC 3.1.13: Exoribonucleases producing 5'-phosphomonoesters
  • EC 3.1.14: Exoribonucleases producing 3'-phosphomonoesters
  • EC 3.1.15: Exonucleases active with either ribo- or deoxyribonucleic acids and producing 5'-phosphomonoesters
  • EC 3.1.16: Exonucleases active with either ribo- or deoxyribonucleic acids and producing 3'-phosphomonoesters
• Endonucleases (deoxyribonucleases and ribonucleases)
  • EC 3.1.21: Endodeoxyribonucleases producing 5'-phosphomonoesters
  • EC 3.1.22: Endodeoxyribonucleases producing 3'-phosphomonoesters
  • EC 3.1.23: Site specific endodeoxyribonucleases: cleavage is sequence specific (discontinued)
  • EC 3.1.24: Site specific endodeoxyribonucleases: cleavage is not sequence specific (discontinued)
  • EC 3.1.25: Site-specific endodeoxyribonucleases specific for altered bases
  • EC 3.1.26: Endoribonucleases producing 5'-phosphomonoesters
    • RNase H
  • EC 3.1.27: Endoribonucleases producing 3'-phosphomonoesters
  • EC 3.1.30: Endoribonucleases active with either ribo- or deoxyribonucleic acids and producing 5'-phosphomonoesters
  • EC 3.1.31: Endoribonucleases active with either ribo- or deoxyribonucleic acids and producing 3'-phosphomonoesters

[edit] See also

• Enzyme
• List of enzymes
• Carboxylic acid
• Ester
• Leukocyte esterase
• Hemagglutininesterase
• Nuclease

[edit] External links

• Enzyme nomenclature