Enzymatic activity

Peroxisomes are pivotal metabolic organelles that exist in almost all eukaryote cells. A reduction in numbers and enzymatic activities of peroxisomes was found in colon adenocarcinomas. However, the role of peroxisomes or the peroxisome pathway in colorectal cancer (CRC) is not defined.

17p vielonmusk 21-01-2022 12 0   Download

In this study, 341 Bacillus sp. strains were isolated from agricultural soils of Turkey. The potent extracellular lipase producer was selected. It was identified by 16S rRNA, named as Bacillus cereus ATA179. Optimal nutritional and physical parameters for lipase production were determined. Sucrose as the carbon source, (NH4 )2 HPO4 as the nitrogen source, CaCl2 as the metal ion were obtained. The best results of physical parameters were stated at 45°C, pH 7.0, shaking rate 50 rpm, inoculation amount 7% and inoculum age 24 h.

14p thiencuuchu 27-11-2021 18 2   Download

The metabolic activities of the casein peptides were verified using purified enzymatic inhibition studies. The regulatory enzyme inhibition led us to conclude a positive correlation with the role of casein peptides in modulating the diabetic and hypertensive metabolic pathways in the biological system. Purified enzymes were used for the investigation to clearly observe the direct impact on the diabetes and hypertension related bioprocesses.

10p nguaconbaynhay7 15-08-2020 15 1   Download

A pot culture experiment was conducted to study the effect of humic acid on soil microbial population and enzymatic activity in groundnut in an Alfisol at Main Agricultural Research Station, Dharwad.

5p gaocaolon5 14-06-2020 5 1   Download

We study the enzymatic hydrolysis of lactose by a commercial enzyme from a selected strain of Kluyveromyces fragilis. The variables analyzed were: temperature (25–40 ◦C), enzyme concentration (0.1–3.0 g l−1), lactose concentration (0.0278–0.208 M), and initial galactose concentration (0.0347 M). On the basis of the data analyzed, both published and in the present work, we propose a Michaelis–Menten kinetic model with inhibition by the product (galactose), which reveals that the substrate (lactose) and the product (galactose) present similar affinity for the active site of the enzyme.

10p abk1996 04-09-2018 33 1   Download

With the aim to distinguish between local and global conformational changes induced by trifluoroethanol in RNase A, spectroscopic and activity measurements in combination with proteolysis by unspecific proteases have been exploited for probing structural transitions of RNase A as a function of trifluoroethanol concentration. At 30% (v/v) trifluoroethanol (pH 8.0; 25 °C), circular dichroism and fluorescence spectroscopy indicate a cooperative collapse of the tertiary structure of RNase A coinciding with the loss of its enzymatic activity....

7p system191 01-06-2013 47 3   Download

An exo-1,3-b-glucanase has been isolated from cultural filtrate of Trichoderma viride AZ36. The N-terminal sequence of the purified enzyme (m ¼ 61 ^ 1 kDa) showed no significant homology to other known glucanases. The 1,3-b-glucanase displayed high activity against laminarins, curdlan, and 1,3-b-oligoglucosides, but acted slowly on 1,3-1,4-b-oligoglucosides. No significant activity was detected against high molecular mass 1,3-1,4-bglucans. The enzyme carried out hydrolysis with inversion of the anomeric configuration.

9p system191 01-06-2013 44 6   Download

This study investigated the enzymatic function of two putative plant GPXs, GPXle1 from Lycopersicon esculentum and GPXha2 from Helianthus annuus, which show sequence identities with the mammalian phospholipid hydroperoxide glutathione peroxidase (PHGPX). Both purified recombinant proteins expressed in Escherichia coli show PHGPX activity by reducing alkyl, fatty acid and phospholipid hydroperoxides but not hydrogen peroxide in the presence of glutathione.

7p research12 01-06-2013 37 4   Download

Nuclear receptors (NRs) are ligand-regulated, DNA-binding transcription factors that function in the chromatin environment of the nucleus to alter the expression of subsets of hormone-responsive genes. It is clear that chromatin, rather than being a passive player, has a profound effect on both transcriptional repression and activation mediated by NRs.

9p research12 01-06-2013 32 2   Download

By replacing specific amino acids at positions 112, 147 and 152 of the human aldosterone synthase (CYP11B2) with the corresponding residues from human, mouse or rat 11b-hydroxylase (CYP11B1), we have been able to investigate whether these residues belong to structural determinants of individual enzymatic activities. When incubated with 11-deoxycorticosterone (DOC), the 11b-hydroxylation activity of the mutants was most effectively increased by combining D147E and I112P (sixfold increase).

10p research12 01-06-2013 35 4   Download

We have recently expressed in bacteria the enzymatically active reverse transcriptase (RT) of bovine leukemia virus (BLV) [Perach, M. & Hizi, A. (1999) Virology 259, 176–189]. In the present study, we have studied in vitro two features of the DNA polymerase activity of BLV RT, the processivity of DNA synthesis and the fidelity of DNA synthesis. These properties were compared with those of the well-studied RTs of human immunodeficiency virus type 1 (HIV-1) and murine leukaemia virus (MLV).

9p research12 01-06-2013 42 4   Download

The thermal stabilityofperoxidase fromleavesof theAfrican oil palm treeElaeis guineensis(AOPTP) at pH 3.0 was studied by differential scanning calorimetry (DSC), intrinsic fluorescence, CD and enzymatic assays.The spectral parameters asmonitoredby ellipticity changes in the far-UV CD spectrum of the enzyme as well as the increase in tryp-tophan intensity emission upon heating, together with changes in enzymatic activity with temperature were seen to be good complements to the highly sensitive but integral methodofDSC....

7p research12 29-04-2013 45 3   Download

Glutathione reductase (GR) recycles oxidized glutathione (GSSG) by converting it to the reduced form (GSH) using an NADPH as the electron source. The function of GR in the male genital tract of the rat was examined by meas-uring its enzymatic activity and examining the gene expression and localization of the protein.

9p research12 29-04-2013 46 3   Download

Theb1,3-glycosyltransferase enzymes identi®ed to date share several conserved regions and conserved cysteine res-idues, all being located in the putative catalytic domain. To investigate the importance of these motifs and cysteines for the enzymatic activity, 14 mutants of the murine b1,3-galactosyltransferase-I gene were constructed and expressed in Sf9 insect cells. Seven mutations abolished the galacto-syltransferase activity.

7p research12 29-04-2013 38 3   Download

It is scientifically and industrially important 1 to clarify the stabilizing mechanism of proteases in extraordinary envi-ronments. We used subtilisins ALPI and Sendai as models to study the mechanism. Subtilisin ALPI is extremely sensitive to highly alkaline conditions, even though the enzyme is produced by alkalophilicBacillus, whereas sub-tilisin Sendai from alkalophilic Bacillusis stable under conditions of high alkalinity.

9p research12 23-04-2013 43 1   Download

Reactionof certainpeptides andproteinswithsingletoxygen (generated by visible light in the presence of rose bengal dye) yields long-lived peptide and protein peroxides. Incubation of these peroxides with glyceraldehyde-3-phosphate dehy-drogenase, in the absence of addedmetal ions, results in loss of enzymatic activity. Comparative studies with a range of peroxides have shown that this inhibition is concentration, peroxide, and time dependent, with H2O2less ecient than some peptide peroxides.

10p research12 23-04-2013 38 4   Download

The mature cysteine protease from Dermatophgoides pteronyssinus, Der p 1, is a major house dust mite allergen. Its enzymatic activity has been shown to have pro-in¯am-matory e€ects that could alsonegatively in¯uence ecacy of allergen-speci®c immunotherapy. The aimof this study was to express recombinant pro-Der p 1 (rpro-Der p 1) in the yeastPichia pastorisand to study itsmaturation.

9p research12 23-04-2013 30 2   Download

A novel nucleosidase enzymatic activity was discovered in the marine spongeAxinella polypoides. This enzyme, desig-nated as ATP N-glycosidase, converts adenosine-5¢-tri-phosphate into adenine and ribose-5-triphosphate. The crude extract ofA.polypoideswas capable of hydrolysing 25lmol ATPÆmin )1 per g wet weight of sponge. The cata-lytic activity of a sponge crude extract permg total protein is comparable with specific activities of purified plant adeno-sine and bacterial AMP nucleosidases.

11p tumor12 20-04-2013 55 3   Download

Earlier we presented several lines of evidence that a 67-kDa laminin binding protein (LBP) inLeishmania donovani,that is different from the putative mammalian 67-kDa laminin receptor, may play an important role in the onset of leish-maniasis, as these parasites invade macrophages in various organs after migrating through the extracellular matrix. Here we describe the membrane orientation of thisLeish-manialaminin receptor.

8p tumor12 20-04-2013 45 4   Download

Novel chromogenic substrates for endo-b-galactosidase were designed on the basis of the structural features of keratan sulfate. Galb1-4GlcNAcb1-3Galb1-4GlcNAcb-pNP (2),which consists of two repeating units ofN-acetyl-lactosamine,was synthesized enzymatically by consecutive additions of GlcNAc and Gal residues top-nitrophenyl b-N-acetyllactosaminide. In a similar manner,Glc-NAcb1-3Galb1-4GlcNAcb-pNP (1),GlcNAcb1-3Galb1-4Glcb-pNP (3),Galb1-4GlcNAcb1-3Galb1-4Glcb-pNP (4), Galb1-3GlcNAcb1-3Galb1-4Glcb-pNP (5),and Galb1-6GlcNAcb1-3Galb1-4Glcb-pNP (6) were synthesized as analogues of2.

11p tumor12 20-04-2013 28 2   Download