Esterase

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

Esterase polymorphism and sensitivity to Dursban organophosphorus insecticide in Culex pipiens pipiens populations.

Abstract: Esterase polymorphism and Dursban (O,O-dimethyl-2-pyridylphosphorothioate) sensitivity have been investigated in 12 natural populations and three laboratory strains of Culex pipiens pipiens. This mosquito has two esterase loci, Est-1 and Est-2, which were shown to code esterases of the B group (aliesterases) but not cholinesterases. No correlation between Est-1 polymorphism and Dursban sensitivity was found, but the increase of the Est-20.64 allele in the populations less sensitive to Dursban was highly significant (r=−0.9850 for 6 df).

Biochemical genetics of rat esterases: polymorphism, tissue expression and linkage of four loci

Abstract: Two alleles at each of four esterase loci in Rattus norvegicus are described with regard to tissue expression, electrophoretic characterization, and genetic linkage. A previously described dominant gene for prealbumin serum esterase is demonstrated to exist as two codominant alleles in the genetically determined absence of the characteristic albumin esterase. The allelic composition of 16 inbred strains for four esterase genes is provided, and the heretofore ambiguous nomenclature of rat esterase genetics is standardized. Linkage of Es-1, Es-2, and Es-3 is demonstrated. Es-2 and Es-3 are tightly linked in that no recombination has been observed in 55 offspring. The same offspring demonstrated 9% recombination between Es-1 and the other two loci.

Novel fluorescent phosphonic acid esters for discrimination of lipases and esterases.

Abstract: Lipases and esterases are responsible for carboxylester hydrolysis inside and outside cells and are useful biocatalysts for (stereo)selective modification of synthetic substrates. Here we describe novel fluorescent suicide inhibitors that differ in structure and polarity for screening and discrimination of lipolytic enzymes in enzyme preparations. The inhibitors covalently react with the enzymes to form fluorescent lipid-protein complexes that can be resolved by gel electrophoresis. The selectivities of the inhibitors were determined by using different (phospho)lipase, esterase and cholesterol esterase preparations. The results indicate that formation of an inhibitor-enzyme complex is highly dependent on the chemical structure of the inhibitor. We identified inhibitors with very low specificity, and other derivatives that were highly specific for certain subgroups of lipolytic enzymes such as lipases and cholesterol esterases. A combination of these substrate-analogous activity probes represents a useful toolbox for rapid identification and classification of serine hydrolase enzymes.

Purification and molecular properties of an unspecific carboxylesterase (E1) from rat-liver microsomes.

Abstract: 1 The isolation of an unspecific carboxylesterase from rat liver microsomes is reported. The purification is 66-fold at a yield of about 20%. The enzyme is one of 5 esterase/amidase variants recently separated and corresponds to the fraction designated E1. 2 The enzyme is homogeneous in disc electrophoresis, dodecylsulfate-polyacrylamide gel electrophoresis and in analytical ultracentrifugation, but exhibits slight heterogeneity in isoelectric focusing. 3 Its amino acid composition is presented. 4 The molecular weight of rat liver esterase E1 is 177000 (equilibrium sedimentation), the subunit weight 61 500 (dodecylsulfate disc electrophoresis), and the equivalent weight 66000 (titration with bis[p-nitrophenyl]phosphate). After cross-linking of the enzyme by dimethyl suberimidate and dodecylsulfate-polyacrylamide gel electrophoresis three principal bands are observed. Therefore, a trimeric structure in which each subunit possesses one active site is proposed.

Active and Passive Immunizations with the Streptococcal Esterase Sse Protect Mice against Subcutaneous Infection with Group A Streptococci

Abstract: The human pathogen group A Streptococcus (GAS) produces many secreted proteins that play important roles in GAS pathogenesis, including hydrolases that degrade proteins and nucleic acids. This study targets another kind of hydrolase, carboxylic esterase, with the objectives of identifying GAS esterase and determining whether it is a protective antigen. The putative esterase gene SPy1718 was cloned, and the recombinant protein (Sse) was prepared. Sse was detected in GAS culture supernatant, and patients with streptococcal pharyngitis seroconverted to Sse, indicating that Sse was produced in vivo and in vitro. Sse hydrolyzes p-nitrophenyl butyrate, and the residue 178Ser is critical for this esterase activity. There are two Sse variant complexes according to the available genome databases, consistent with the previous finding of two antigenic Sse variants. Complex I includes serotypes M1, M2, M3, M5, M6, M12, and M18, whereas M4, M28, and M49 belong to complex II. Sse variants share >98% identity in amino acid sequence within each complex but have about 37% variation between the two groups. Active immunization with M1 Sse significantly protects mice against lethal subcutaneous infection with virulent M1 and M3 strains and inhibits GAS invasion of mouse skin tissue. Passive immunization with anti-Sse antiserum also significantly protects mice against subcutaneous GAS infection, indicating that the protection is mediated by Sse-specific antibodies. The results suggest that Sse plays an important role in tissue invasion and is an antigen protective in subcutaneous infection against GAS strains of more than one serotype.