Esterase

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

Complement as a mediator of inflammation iii. purification of the activity with anaphylatoxin properties generated by interaction of the first four components of complement and its identification as a cleavage product of c'3

Abstract: Purified preparations of human C'1 esterase, C'4, C'2, C'3, and C'5 were labeled with 125I. Reaction mixtures were prepared containing a single labeled component and other unlabled components. After incubation at 37°C for 10 min at pH 7.4 in the presence of 5 x 10–4 M Mg2+, they were adjusted to pH 3.5 and subjected to sucrose density gradient ultracentrifugation and gel filtration at pH 3.5. In all cases, an activity capable of contracting guinea pig ileum with tachyphylaxis was obtained in low molecular weight fractions. However, these fractions were labeled only when 125I-C'3 was employed, indicating that biological activity was associated with a cleavage product of C'3. This fragment has been designated F(a)C'3 in a nomenclature consistent with that of immunoglobulin degradation products. The much larger, residual portion of the C'3 molecule has been designated F(b)C'3. The biochemical characteristics of generation of F(a)C'3 were consistent with a mechanism involving action of C'1 esterase on C'4 and C'2, activation of C'2, and cleavage of C'3. F(a)C'3 had a molecular weight by gel filtration techniques of 6800 or less. It was thermostable and susceptible to inactivation by endo- and exopeptidases. The isolated fragment possessed all of the biological properties of unfractionated mixtures of C'1 esterase, C'4, C'2, and C'3. In addition to contraction of guinea pig ileum, these included failure to contract rat uterus, enhancement of vascular permeability in guinea pig skin, degranulation of mast cells in guinea pig mesentery, and release of histamine from rat peritoneal mast cells. F(a)C'3 did not cross-desensitize guinea pig ileum to rat agar anaphylatoxin and vice versa. The existence of different protein fragments with anaphylatoxin properties has been discussed. Distinctive characteristics of F(a)C'3 from classical anaphylatoxin generated by treatment of fresh rat serum with agar have been indicated.

Coatings and surface treatments having active enzymes and peptides

Abstract: Disclosed herein are a materials such as a coating, an elastomer, an adhesive, a sealant, a textile finish, a wax, and a filler for such a material, wherein the material includes an enzyme such as an esterase (e.g., a lipolytic enzyme, a sulfuric ester hydrolase, an organophosphorus compound degradation enzyme), an enzyme that degrades a cell wall and/or a cell membrane component (e.g., a lysozyme, a lytic transgrycosylase, a peptidase), and/or a biocidal or biostatic peptide. Also disclosed herein are methods of decontaminating a surface comprising such a material from a chemical substrate of an enzyme such as a lipid or an organophosphorus compound, as well as reducing the growth of a microorganism on or within such a material.

Purification and Properties of a Xylan-Binding Endoxylanase from Alkaliphilic Bacillus sp. Strain K-1

Abstract: An alkaliphilic bacterium, Bacillus sp. strain K-1, produces extracellular xylanolytic enzymes such as xylanases, β-xylosidase, arabinofuranosidase, and acetyl esterase when grown in xylan medium. One of the extracellular xylanases that is stable in an alkaline state was purified to homogeneity by affinity adsorption-desorption on insoluble xylan. The enzyme bound to insoluble xylan but not to crystalline cellulose. The molecular mass of the purified xylan-binding xylanase was estimated to be approximately 23 kDa. The enzyme was stable at alkaline pHs up to 12. The optimum temperature and optimum pH of the enzyme activity were 60°C and 5.5, respectively. Metal ions such as Fe2+, Ca2+, and Mg2+ greatly increased the xylanase activity, whereas Mn2+ strongly inhibited it. We also demonstrated that the enzyme could hydrolyze the raw lignocellulosic substances effectively. The enzymatic products of xylan hydrolysis were a series of short-chain xylooligosaccharides, indicating that the enzyme was an endoxylanase.

A Novel Lipolytic Enzyme Located in the Outer Membrane of Pseudomonas aeruginosa

Abstract: A lipase-negative deletion mutant of Pseudomonas aeruginosa PAO1 still showed extracellular lipolytic activity toward short-chain p-nitrophenylesters. By screening a genomic DNA library of P. aeruginosa PAO1, an esterase gene, estA, was identified, cloned, and sequenced, revealing an open reading frame of 1,941 bp. The product of estA is a 69.5-kDa protein, which is probably processed by removal of an N-terminal signal peptide to yield a 67-kDa mature protein. A molecular mass of 66 kDa was determined for 35S-labeled EstA by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. The amino acid sequence of EstA indicated that the esterase is a member of a novel GDSL family of lipolytic enzymes. The estA gene showed high similarity to an open reading frame of unknown function located in the trpE-trpG region of P. putida and to a gene encoding an outer membrane esterase of Salmonella typhimurium. Amino acid sequence alignments led us to predict that this esterase is an autotransporter protein which possesses a carboxy-terminal β-barrel domain, allowing the secretion of the amino-terminal passenger domain harboring the catalytic activity. Expression of estA in P. aeruginosa and Escherichia coli and subsequent cell fractionation revealed that the enzyme was associated with the cellular membranes. Trypsin treatment of whole cells released a significant amount of esterase, indicating that the enzyme was located in the outer membrane with the catalytic domain exposed to the surface. To our knowledge, this esterase is unique in that it exemplifies in P. aeruginosa (i) the first enzyme identified in the outer membrane and (ii) the first example of a type IV secretion mechanism.

A Study of Stereoselective Hydrolysis of Symmetrical Diesters with Pig Liver Esterase

Abstract: Pig liver esterase-(PLE) catalyzed hydrolysis of dimethyl esters of symmetrical dicarboxylic acids, including meso-diacids, cis-1,2-cycloalkanedicarboxylic acids, and diacids with a prochiral center, was studied with 14 substrates. The products of these stereoselective hydrolyses are chiral monoesters of dicarboxylic acids, with an enantiomeric excess (e.e.) from 10% to 100%. Some of these optically active monoesters are valuable synthons in natural products synthesis. An additivity pattern of α- and β-substituents with the glutaric esters on the stereoselectivity of enzymatic hydrolysis was observed. Analysis of the experimental results leads to a model of enzyme stereoselectivity of diester hydrolysis in which the substitution pattern at α- and β-C-atoms is found to determine the absolute configuration of the resulting monoester.