Carboxylic ester hydrolases

According to the IUPAC-IUB Enzyme Nomenclature,11 pectinesterase belongs to the carboxyl ester hydrolases (EC 3.1.1.11) and has the systematic name pectin pectyl-hydrolase. The literature also contains the expressions pectin methylesterase, pectin demethoxylase, and pectin methoxylase for the same enzyme. The old name pectase,... 

A selection of carboxylic ester hydrolases (EC 3.1.1) of major or more-modest significance in xenobiotic metabolism is given in Table 2.5. The recommendations of the Enzyme Nomenclature Committee on the classification of esterases cannot be considered completely satisfactory, but, even after decades of debate, a more satisfactory classification system remains to be proposed [56] [57], The main difficulties with esterase classification have been summarized as follows [58],... 

Table 2.5. A Selection of Carboxylic Ester Hydrolases (EC 3.1.1) Having Some Role in Xenobiotic Metabolism ... 

Carboxylesterase Carboxylic ester hydrolase, nonspecific carboxylesterase, ali-esterase, B-esterase Aliphatic esters... 

F. J. Leinweber, Possible Physiological Roles of Carboxylic Ester Hydrolases , Drug Metab. Rev. 1987, 18, 379-439. 

In addition to these various phosphatases, carboxylic ester hydrolases interact with phosphates and/or phosphonates. The carboxylesterases (EC... 

A-type carboxylic ester hydrolases (arylesterases EC 3.1.1.2), which hydrolyse aromatic esters, e.g. phenylacetate they show little activity on tributyrin, and are not inhibited by organophosphates. 

Lombardo, D., O. Guy, and C. Figarella. 1978. Purification and characterization of a carboxyl ester hydrolase from human pancreatic juice. Biochim Biophys Acta 527 142. 

CL Erisnson-Albertson. Fancrealic carboxyl-ester hydrolase end non-enzymatic constituents of pancreatic juice. In Molecular and Cellular Basis of Digestion (P. Desnuelle, ed.). Elievier, Amsterdam, 193, pp. 297-303. 

Human BSSL shows immunological identity with the carboxyl ester hydrolase in pancreatic juice, and the two enzymes are very similar in molecular and kinetic properties (Blackberg et al., 1981b). In fact, Nilsson... 

In addition to the now well-documented lipase system, cows milk contains several other carboxyl ester hydrolases, collectively referred to as esterases. These are distinguished from lipases by their ability to act on ester substrates in solution rather than in an emulsified form (Jaeger et al., 1994) and/or by their preference for hydrolysing esters of short-chain rather than long-chain acids (Okuda and Fujii, 1968). 

Blackberg, L., Lombardo, D., Hernell, O., Guy, O., Olivecrona, T. 1981b. Bile salt-stimulated lipase in human milk and carboxyl ester hydrolase in pancreatic juice. FEBS Letts 136, 284-288. 

Nilsson, J., Blackberg, L., Carlsson, P., Enerback, S., Hernell, O., Bjursell, G. 1990. cDNA cloning of human-milk bile-salt-stimulated lipase and evidence for its identity to pancreatic carboxylic ester hydrolase. Eur. J. Biochem. 192, 543-550. 

Lipase lipase (1) edible forestomach tissue of (1) carboxylic-ester hydrolase 3.1.1.1... 

AChEs, BuChEs, and CaEs are specialized carboxylic ester hydrolases classed among the B esterases, enzymes that are inhibited by OPs. Another class of enzymes are the A esterases (e.g., paraoxonase and DFPase) that actively hydrolyze OPs, destroying their toxic potential... 

Pancreatic lipase can be considered a model for all other lipases. Most if not all of these enzymes seem to be nonspecific carboxyl ester hydrolases of the serine histidine type. Their specificity consists, by definition, in their ability to hydrolyze insoluble substrates, but apart... 

Enzymes that hydrolyze lysophospholipids are found in nearly all tissues and organisms. They seem to be non-specific esterases of the serine-histidine type (25) and hardly deserve the name lysophospholipase because they also hydrolyze esters other than phospholipids. They should probably be considered together with such enzymes as cholesterol esterases and monoglyceride lipases as amphiphilic carboxyl ester hydrolases. These non-specific esterases have a preference for amphiphilic (hydrophilic-lipophilic) substrates. Such an enzyme may perhaps hydrolyze lysophospholipis, monoglycerides, diglycerides, and cholesterol esters. 

Pig Liver Esterase (PLE). This is the more used car-boxylesterase (carboxylic-ester hydrolase, EC 3.1.1.1, CAS 9016-18-6) which physiologically catalyzes the hydrolysis of carboxylic acid esters to the free acid anion and alcohol. PLE is a serine hydrolase which has been widely used for the preparation of chiral synthons and these applications have been fully reviewed. An active-site model for interpreting and predicting the specificity of the enzyme has been published. In the pioneering studies of the enzyme applications field, PLE was used for the chiral synthesis of mevalonolactone. Prochiral 3-substituted glutaric acid diesters... 

Retinyl esters are hydrolyzed in the intestinal lumen by pancreatic carboxylic ester hydrolase, which also hydrolyzes cholesteryl esters. In mucosal cells, retinol is reesterified, mostly with long-chain fatty acids, by... 

Clement JG, Benschop HP, De Jong LPA, Wolthuis OL. Stereoisomers of soman (pinacolyl methylpho-sphonofiuoridate) inhibition of serum carboxylic ester hydrolase and potentiation of their toxicity by CBDP (2-2-methylphenoxy)-4H-l,3,2-benzodioxaphosphorin-2-oxide in mice. Toxicol Appl Pharmacol, 1987 89 141-143. 

Hydrolases. Hydrolases constitute a very complex ensemble of enzymes many of which are known or suspected to be involved in xenobiotic metabolism. Relevant enzymes among the serine hydrolases include carboxy-lesterases (carboxylic-ester hydrolase EC... 

Carboxylic ester-containing chemicals are very efficiently hydrolyzed into the respective free acids by a class of enzyme designated as carboxylic ester hydrolases (EC 3.1.1). Unfortunately, because these widely occurring enzymes exhibit broad and overlapping substrate specificity toward esters and amides, and because, in many cases, their exact physiological role remains unclear, their classification is difficult (39-45). According to an older but still used classification system (46), the more important subclasses include carboxyl-... 

Faber K (1998) Carboxylic Ester Hydrolases for Asymmetric Syntheses, Merck-Schuchardt Info 1998... 

Methods have been published that allow the classification of two types of esterases, the carboxylic ester hydrolases (CEHs) and the phosphoric triester hydrolases (PTEHs) (Anspaugh and Roe, 2004). The CEHs contain the B-esterases, which are inhibited by organophosphates. B-esierases include many other esterases, such as CarbE, acetylcholinesterase (AChE), cholinesterases (ChE), aryleslerases, sterol esterases, insect juvenile hormone esterases, aixl others. The determination of A-esterases uses a protocol for the detection of PTEHs. The PTEH assay allows for the identification of two subclasses of esterases, the A-esterase (known as aiyldialkylphos-phatase) and ditsopropyl fluorophosphatase. Both these enzymes metabolize OP compounds. 

Anspaugh, D, D., and Roe, R. M. (2004). Assays for the classification of two tyjjes of esterases Carboxylic ester hydrolases and phosphoric triestcr hydrolases. In Current Protocols in Toxicology, pp. 4.10.1-4,10,9. Wiley, New York. 

Lauridsen, C., Hedemann, M.S., and Jensen, S.K., Hydrolysis of tocopheryl and retinyl esters by porcine carboxyl ester hydrolase is affected by their carboxylate moiety and bile acids, J. Nutr. Biochem. 12 (4), 219-224, 2001. 

Esterases (EC 3.1) are a subclass of enzymes that catalyze the hydrolysis of esters to carboxylic acids and alcohols. Carboxylic ester hydrolases (EC 3.1.1)... 

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