Esterase

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

Cloning and Nucleotide Sequence of Thermostable Lipase Gene from Pseudomonas fluorescens SIK W1

Abstract: A gene coding for a thermostable lipase of Pseudomonas fluorescens SIK W1 was cloned into Escherichia coli JM83 by inserting Sau3AI-generated DNA fragments into the BamHI site of pUC19. Twenty colonies with esterase activity on the tributyrin agar plate were isolated by screening the constructed Pseudomonas fluorescens genomic library. Only one out of the esterase positive 20 colonies had lipase activity on the agar plate containing olive oil and Rhodamine-B.The complete nucleotide sequence of the lipase gene was identified. The lipase gene consists of an open reading frame, 1347 bp long, commencing with an ATG start codon encoding a polypeptide of 449 amino acid residues and a TGA stop codon. Comparison of this lipase amino acid sequence with those from another organisms sequenced to data showed the presence of the short homologous region Gly-X-Ser-X-Gly.

A case of hereditary angioneurotic oedema, successfully treated with epsilon-aminocaproic acid. Studies on C'1 esterase inhibitor, C'1 activation, plasminogen level and histamine metabolism.

Abstract: A patient with clinical and laboratory findings characteristic of hereditary angioneurotic oedema was investigated. The patient was observed for a period of 5 weeks, during which he had four attacks. e-Aminocaproic acid (EACA) was then given continuously for 5 months, during which time the patient had no attacks. Attacks reappeared on withdrawal of EACA. Trans-4-(aminomethyl) cyclohexane carboxylic acid (AMCA®) was found to be equally effective in later therapeutic trials. C'1 esterase inhibitor was found in low concentration in defibrinated plasma also during attacks. e-Aminocaproic acid (EACA) produced no significant change of the inhibitor content. C'1 esterase inhibitor disappeared on incubation of defibrinated plasma from the patient at 37°C for 40 min, and C'1 esterase was generated. The generation time of C'1 esterase increased with increasing the concentration of EDTA in the test solution. The C'1 esterase inhibitor content of defibrinated plasma from the patient, varied with the C'1 esterase generation time, the coefficient of correlation being higher in plasma sampled before treatment with EACA. Plasminogen and α2-macroglobulin were within the normal ranges, also during attacks. EACA markedly depressed the plasminogen level, which rapidly returned to normal on withdrawal of the drug. The studies on histamine metabolism revealed no significant changes with the exception of the urinary excretion of histamine, which was moderately increased towards the end of the period studied. On the days the patient received EACA the urine never contained 1-methylimidazole-5-acetic acid which was present in all the other specimens of urine examined. The basal gastric acid secretion was increased.

Characterization and structural modeling of a new type of thermostable esterase from Thermotoga maritima.

Abstract: A bioinformatic screening of the genome of the hyperthermophilic bacterium Thermotoga maritima for ester-hydrolyzing enzymes revealed a protein with typical esterase motifs, though annotated as a hypothetical protein. To confirm its putative esterase function the gene (estD) was cloned, functionally expressed in Escherichia coli and purified to homogeneity. Recombinant EstD was found to exhibit significant esterase activity with a preference for short acyl chain esters (C4-C8). The monomeric enzyme has a molecular mass of 44.5 kDa and optimal activity around 95 degrees C and at pH 7. Its thermostability is relatively high with a half-life of 1 h at 100 degrees C, but less stable compared to some other hyperthermophilic esterases. A structural model was constructed with the carboxylesterase Est30 from Geobacillus stearothermophilus as a template. The model covered most of the C-terminal part of EstD. The structure showed an alpha/beta-hydrolase fold and indicated the presence of a typical catalytic triad consisting of a serine, aspartate and histidine, which was verified by site-directed mutagenesis and inhibition studies. Phylogenetic analysis showed that EstD is only distantly related to other esterases. A comparison of the active site pentapeptide motifs revealed that EstD should be grouped into a new family of esterases (Family 10). EstD is the first characterized member of this family.

A comparison by the use of gel electrophoresis of soluble protein components and esterase enzymes of some group D Streptococci.

Abstract: Surmmary Soluble cell constituents of strains of Streptococcus faecalis, S. faecium and S. durans were studied by electrophoresis in polyaery lamide gels followed by staining the gel to reveal the patterns of separated proteins and esterase enzymes. The patterns of proteins and of esterases found in S. faecalis differed from those in S. faecium and S. durans. Strains of S. faecalis differing in serotype and variety showed a very similar series of proteins, some differences in patterns of esterases were found, but similar patterns occurred in strains differing in type and variety. The major protein bands of S. faecium and S. durans differed in mobility from the major proteins of S. faecalis; different strains of S. faecium and S. durans showed some differences in other protein bands. Esterase activity of S. faecium and S. durans was weaker than that of S. faecalis, and in the case of most strains only faint esterase bands were detected. A strain of S. faecium which gave protein and esterase patterns different from those of the remaining strains, differed also in showing motility.