Oxidative physiology

The results showed that the overall diffusioncontrolled rate constant is equal to 4.82×109 M-1 s -1 at 298.15K. The zwitterionic form is the main existing form that plays an essential role in the HO - initiated oxidation of Ile (99.98%). The most preponderant reactions are found at C6-H (36.19%) and C8-H (37.77%) positions. Finally, the influence of temperature on the overall rate is also evaluated.

8p dianmotminh02 03-05-2024 7 2   Download

Zinc is used as an anti-gingivitis agent in oral care products and affects multiple targets in oral bacteria. We found that it acts also to suppress respiration of oral streptococci and of Fusobacterium nucleatum, an organism associated with development of gingivitis.

9p 12120609 01-06-2020 19 1   Download

The signaling properties of the gasotransmitter molecule hydrogen sulfide (H2S), which is endogenously generated in plant cells, are mainly observed during persulfidation, a protein post-translational modification (PTM) that affects redox-sensitive cysteine residues. There is growing experimental evidence that H2S in higher plants may function as a mechanism of response to environmental stress conditions.

7p partimesinhvien 08-05-2020 31 0   Download

Venoms from crotalid and viperid snakes contain several peptide inhibitors which regulate the proteolytic activities of their snake-venom metalloproteinases (SVMPs) in a reversible manner under physiological conditions. In this report, we describe the high-resolution crystal structures of a SVMP, TM-3, from Taiwan habu (Trimeresurus mucrosquamatus) cocrystallized with the endogenous inhibitors pyroGlu-Asn-Trp (pENW), pyroGlu-Gln-Trp (pEQW) or pyroGlu-Lys-Trp (pEKW).

10p system191 01-06-2013 29 5   Download

The physiological role of sulfoquinovosyl diacylglycerol (SQDG) in photosynthesis was investigated with a SQDG defective mutant (hf-2) of Chlamydomonas reinhardtii that did not have any detectable amount of SQDG. The mutant showed a lower rate of photosystem II (PSII) activity by  40% and also a lower growth rate than those of the wildtype. Results of genetical analysis of hf-2 strongly suggest that the SQDG defect and the lowered PSII activity are due to a single gene mutation.

6p research12 01-06-2013 37 6   Download

Nitric oxide (NO), the principal endogenous ligand for soluble guanylate cyclase (sGC), stimulates that enzyme and accumulation of intracellular cGMP, which mediates many of the (patho) physiological effects of NO. Previous studies demonstrated that 2-substituted adenine nucleotides, including 2-methylthioATP (2MeSATP) and 2-chloroATP (2ClATP), allosterically inhibit guanylate cyclase C, the membrane-bound receptor for the Escherichia coli heatstable enterotoxin in the intestine. The present study examined the effects of 2-substituted adenine nucleotides on crude and purified sGC. ...

8p research12 01-06-2013 36 4   Download

Oviparously developing embryos of the brine shrimp, Artemia franciscana, synthesize abundant quantities of a small heat shock/a-crystallin protein, termed p26. Wild-type p26 functions as a molecular chaperone in vitro and is thought to help encysted Artemia embryos survive severe physiological stress encountered during diapause and anoxia. Full-length and truncated p26 cDNA derivatives were generated by PCR amplification of p26-3-6-3, then cloned in either pET21(+) or pRSETC and expressed in Escherichia coli BL21(DE3)....

10p research12 01-06-2013 56 5   Download

Hyaluronan-binding protein 1 (HABP1), a ubiquitous multifunctional protein, interacts with hyaluronan, globular head of complement component 1q (gC1q), and clustered mannose and has been shown to be involved in cell sig-nalling.In vitro, this recombinant protein isolated from human ®broblast exists in di€erent oligomeric forms, as is evident from the results of various independent techniques in near-physiological conditions.

9p research12 29-04-2013 29 4   Download

Plant lipoxygenases (LOXs) are a class of dioxygenases which display diverse functions in several physiological processes such as growth, development and response to biotic and abiotic stresses.Even though LOXs have been characterized from several plant species, the physiological role of seed LOXs is still unclear.With the aim to better clarify the occurrence of LOXs and their influence on hazelnut seed quality, we carried out the biochemical and molecular characterization of the main LOX isoforms expressed during seed development....

11p tumor12 20-04-2013 34 4   Download

The chaperone calreticulin is a highly conserved eukaryotic protein mainly located in the endoplasmic reticulum. It contains a free cysteine SH group but does not form disul-fide-bridged dimers under physiological conditions,indica-ting that the SH group may not be fully accessible in the native protein. Using PAGE,urea gradient gel electro-phoresis,capillary electrophoresis and MS,we show that dimerization through the SH group can be induced by lowering the pH to 5–6,heating,or under conditions that favour partial unfolding such as urea concentrations above 2.

9p tumor12 20-04-2013 39 4   Download

On chemokine stimulation, leucocytes produce and secrete proteolytic enzymes for innate immunedefencemechanisms. Some of these proteasesmodify the biological activity of the chemokines. For instance, neutrophils secrete gelatinase B (matrix metalloproteinase-9, MMP-9) and neutrophil col-lagenase (MMP-8) after stimulation with interleukin-8/ CXCL8 (IL-8). Gelatinase B cleaves and potentiates IL-8, generating a positive feedback.

11p tumor12 20-04-2013 69 4   Download

The ethanol utilization pathway inAspergillus nidulansis a model system, which has been thoroughly elucidated at the biochemical, genetic and molecular levels. Three main ele-ments are involved: (a) high level expression of the positively autoregulated activator AlcR; (b) the strong promoters of the structural genes for alcohol dehydrogenase (alcA)and aldehyde dehydrogenase (aldA); and (c) powerful activa-tion of AlcRby the physiological inducer, acetaldehyde, produced from growth substrates such as ethanol and L-threonine. ...

10p tumor12 20-04-2013 21 2   Download

Anti-Ras intracellular antibodies inhibit cell proliferation in vivo by sequestering the antigen and diverting it from its physiological location [Lener,M.,Horn, I.R.,Cardinale,A., Messina, S., Nielsen, U.B., Rybak, S.M., Hoogenboom, H.R., Cattaneo, A., Biocca, S. (2000)Eur. J. Biochem.267, 1196–1205]. Here we demonstrate that strongly aggregating single-chain antibody fragments (scFv), binding to Ras, induce apoptosis, and this effect is strictly related to the antibody-mediated aggregation of p21Ras.

9p tumor12 20-04-2013 39 3   Download

Lactoferrin (LF) is a Fe 3+ -binding glycoprotein, first recognized in milk and then in other human epithelial secretions and barrier fluids. Many different functions have been attributed to LF, including protection from iron-induced lipid peroxidation, immunomodulation and cell growthregulation, DNA binding, and transcriptional acti-vation. Its physiological role is still unclear, but it has been suggested to be responsible for primary defense against microbial and viral infection.

9p tumor12 20-04-2013 36 3   Download

The physiological role of a bifunctional enzyme, 3,4-dihydrocoumarin hydrolase (DCH), which is capable of both hydrolysis of ester bonds and organic acid-assisted bromination of organic compounds, was investigated. Purified DCH fromAcinetobacter calcoaceticusF46 cata-lysed dose- and time-dependent degradation of peracetic acid. The gene (dch) was cloned from the chromosomal DNA of the bacterium.

9p tumor12 20-04-2013 37 3   Download

ADH1 and ADH4 are the major alcohol dehydrogenases (ADH) in ethanol and retinol oxidation. ADH activity and protein expression were investigated in rat gastrointestinal tissuehomogenates by enzymatic andWesternblot analyses. In addition, sections of adult rat gastrointestinal tract were examined byin situ hybridization and immunohistochem-istry.ADH1andADH4weredetectedalong thewhole tract, changing their localization and relative content as a function of the area studied.

11p fptmusic 16-04-2013 34 2   Download

Calcium metabolism in oysters is a very complicated and highly controlled physiological and biochemical process. However, the regulation of calcium metabolism in oyster is poorly understood. Our previous study showed that calmodulin (CaM) seemed to play a regulatory role in the process of oyster calcium metabolism. In this study, a full-length cDNA encoding a novel calmodulin-like protein (CaLP) with a long C-terminal sequence was identi-fied from pearl oysterPinctada fucata, expressed in Escherichia coliand characterizedin vitro. ...

12p fptmusic 12-04-2013 40 3   Download

To assess the expression and physiological role of the mitochondrial NAD + -independent lactate dehydrogenase (iLDH) inEuglena gracilis, cells were grown with different carbon sources, and theD-andL-iLDHactivities and several key metabolic intermediates were examined. iLDH activity was significant throughout the growth period, increasing by three- to fourfold from latency to the stationary phase. Intracellular levels ofD-andL-lactate were high (5–40 mM) fromthe start of the culture and increased (20–80 mM)when the stationaryphasewas entered....

10p fptmusic 12-04-2013 37 1   Download

The Sir2 family of histone⁄protein deacetylases (sirtuins) is comprised of homologues found across all kingdoms of life. These enzymes catalyse a unique reaction in which NAD + and acetylated substrate are converted into deacetylated product, nicotinamide, and a novel metabolite O-acetyl ADP-ribose. Although the catalytic mechanism is well conserved across Sir2 family members, sirtuins display differential specificity toward acetyl-ated substrates, which translates into an expanding range of physiological functions. ...

10p fptmusic 11-04-2013 41 3   Download

Dehydroepiandrosterone (DHEA), a steroid hormone, modified the proli-feration of human umbilical vein endothelial cells in a dose-dependent manner. Its inactive sulfate ester (DHEA-S) and two of its metabolites – estradiol and testosterone – had no inhibitory effect at physiological concentrations. Antiproliferation was associated with arrest in the G1 phase of the cell cycle, but not with cell death, as evaluated by cleavage of poly(ADP-ribose) polymerase and exposure of phosphatidylserine. ...

0p awards 06-04-2013 38 4   Download