Esterase

About: Esterase is a research topic. Over the lifetime, 7622 publications have been published within this topic receiving 168270 citations.

Purification of tributyrin esterase from Lactococcus lactis subsp. cremoris E8

Abstract: A tributyrin esterase was purified from Lactococcus lactis subsp. cremoris E8 using FPLC chromatography. This was the major esterase activity observed in strain E8 and was associated with a single protein with a subunit molecular mass of 29 kDa and a holoenzyme of molecular mass 109 kDa. The enzyme was active against tributyrin and p-nitrophenyl butyrate. The N-terminal sequence of the enzyme was determined. The enzyme had a pH optimum in the neutral range, was stable on freezing at −20 °C, and had a half life of 1 h at 50 °C.

Relationship between lipase and esterase

Abstract: There are at least two sites on the lipase which are concerned with catalysis: the catalytic site and the hydrophobic recognition site (lipid-binding site). The recognition site may be destroyed by mild proteolytic digestion, but the catalytic site may not be changed by this treatment. Mild treatment with trypsin caused change in the catalytic properties of hepatic triglyceride lipase; the water-insoluble ester-hydrolyzing activity of hepatic triglyceride lipase decreased, whereas the water-soluble ester-hydrolyzing activity did not change. After proteolytic digestion, hepatic triglyceride lipase resembles esterase since it hydrolyzes the water-soluble substrate better than the water-insoluble substrate. Conversely, esterase was converted to lipase by treatment with phospholipid. Cardiolipin in a concentration-dependent fashion enhanced triolein-hydrolysis of human serum carboxylesterase and this effect was associated with a dose-dependent decrease in water-soluble tributyrin hydrolysis. Based on these results, we propose the hypothesis that lipase and esterase have similar catalytic sites and that addition of a hydrophobic recognition site to esterase causes conversion of esterase to lipase (Fig. 9).

The enzymatic hydrolysis of a synthetic biomembrane: a new substrate for cholesterol and carboxyl esterases.

Abstract: With the introduction of artificial implant devices, a new host of biomembrane-like structures have been introduced into the bio-media made up of the synthetic matrix, adsorbed proteins and lipids. Lysosomal hydrolases, e.g. cholesterol esterase (CE), are implicated during the tissue response near the tissue-implant interface. The enzymatic attack on a radiolabelled 'hybrid biomembrane', a polyester-urethane (PUU-CAP), was investigated using two esterases. Membrane stability was monitored by release of radiolabelled molecules. Although some radioactivity was released by buffer controls, upon the addition of CE, a burst of radiolabel release occurred which was due to an enzymatic reaction that could be saturated and inhibited by the specific esterase inhibitor, phenylmethylsulfonylfluoride. Carboxyl esterase (CXE) incubation with PUU-CAP caused less radiolabel release than CE which was similar to the latter's activity when common nitrophenyl ester substrates were used. When a factorial analysis was perform...

Biochemical Characterization and Relative Expression Levels of Multiple Carbohydrate Esterases of the Xylanolytic Rumen Bacterium Prevotella ruminicola 23 Grown on an Ester-Enriched Substrate

Abstract: We measured expression and used biochemical characterization of multiple carbohydrate esterases by the xylanolytic rumen bacterium Prevotella ruminicola 23 grown on an ester-enriched substrate to gain insight into the carbohydrate esterase activities of this hemicellulolytic rumen bacterium. The P. ruminicola 23 genome contains 16 genes predicted to encode carbohydrate esterase activity, and based on microarray data, four of these were upregulated >2-fold at the transcriptional level during growth on an ester-enriched oligosaccharide (XOS FA,Ac) from corn relative to a nonesterified fraction of corn oligosaccharides (AXOS). Four of the 16 esterases (Xyn10D-Fae1A, Axe1-6A, AxeA1, and Axe7A), including the two most highly induced esterases (Xyn10D-Fae1A and Axe1-6A), were heterologously expressed in Escherichia coli, purified, and biochemically characterized. All four enzymes showed the highest activity at physiologically relevant pH (6 to 7) and temperature (30 to 40°C) ranges. The P. ruminicola 23 Xyn10D-Fae1A (a carbohydrate esterase [CE] family 1 enzyme) released ferulic acid from methylferulate, wheat bran, corn fiber, and XOS FA,Ac, a corn fiber-derived substrate enriched in O-acetyl and ferulic acid esters, but exhibited negligible activity on sugar acetates. As expected, the P. ruminicola Axe1-6A enzyme, which was predicted to possess two distinct esterase family domains (CE1 and CE6), released ferulic acid from the same substrates as Xyn10D-Fae1 and was also able to cleave O-acetyl ester bonds from various acetylated oligosaccharides (AcXOS). The P. ruminicola 23 AxeA1, which is not assigned to a CE family, and Axe7A (CE7) were found to be acetyl esterases that had activity toward a broad range of mostly nonpolymeric acetylated substrates along with AcXOS. All enzymes were inhibited by the proximal location of other side groups like 4-O-methylglucuronic acid, ferulic acid, or acetyl groups. The unique diversity of carbohydrate esterases in P. ruminicola 23 likely gives it the ability to hydrolyze substituents on the xylan backbone and enhances its capacity to efficiently degrade hemicellulose.

Characterization of digestive gland esterase-lipase activity of juvenile redclaw crayfish Cherax quadricarinatus.

Abstract: Investigation of esterase–lipase activity in the digestive gland of redclaw crayfish Cherax quadricarinatus showed that the optimum enzyme activity occurred between 35 and 40 °C, with 100 mM NaCl at pH 8.5. Heavy metals completely inhibited and calcium ions partially inhibited enzyme activity. The enzyme activity diminished as the length of the fatty acid chain of substrates increased. Molecular masses for four isozymes were 43, 46, 63 and 118 kDa, respectively, as determined by PAGE.