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1

Influence of 2,5-dichloro-1,4-benzoquinone on jack bean urease activity. Inhibitory effect, total reducing capacity and DPPH radical scavenging activity

100%

Kot M., Olech Z.

Acta Biochimica Polonica

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2011

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tom 58

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nr 4

Inhibition of jack bean activity by 2,5-dichloro-1,4-benzoquinone (DCBQ) was studied in phosphate buffer, pH 7.0. It was found that DCBQ acted as a strong, time and concentration dependent inactivator of urease. Under the experimental conditions obeyed the terms of pseudo-first-order reaction, urease was totally inactivated. Application of Wilson-Kitz method proved that the urease-DCBQ interaction followed a simple bimolecular process and the presence of intermediate complex was undetectable. The determined second order rate constant of the inactivation was 0.053 (μM min)-1. Thiols such as l-cysteine, glutathione and dithiothreitol (DTT) protected urease from inhibition by DCBQ but DCBQ-modified urease did not regain its activity after DTT application. The thiol protective studies indicated an essential role of urease thiol(s) in the inhibition. The irreversibility of the inactivation showed that the process was a result of a direct modification of urease thiol(s) by DCBQ (DCBQ chlorine(s) substitution). The decomposition of DCBQ in aqueous solution at natural light exposure was monitored by visible spectrophotometry, determination of the total reducing capacity (Folin-Ciocalteu method) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging ability. The DCBQ conversion resulted in a decrease of the inhibition power and was well correlated with the increase of the total reducing capacity and DPPH scavenging ability. These findings were attributed to DCBQ transformation by photolysis and the hydrolysis effect was found to be negligible.

2

Effects of homogenization of induced sputum by dithiothreitol on polymorphonuclear cells

100%

Van Overveld F. J., Demkow U., Gorecka D., Skopinska-Rozewska E., De Backer W. A., Zielinski J.

Journal of Physiology and Pharmacology. Supplement

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2005

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tom 56

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nr 4

143-154

Induced sputum represents a useful and non-invasive tool to isolate different cells from the airways. Complete homogenization of sputum is important for dispersion of cells and is usually achieved by use of dithiothreitol (DTT). However, it is not known if DTT will influence the viability and functionality of cells obtained by induced sputum. In the present study, induced sputum was processed by DTT or by PBS treatment. The obtained neutrophils were compared with neutrophils obtained from peripheral blood and from bronchoalveolar lavage fluid (BAL). These isolated neutrophils were treated in a similar way as the sputum neutrophils with DTT or PBS. All isolated cells were used for chemiluminescence tests and for the measurement of elastase and myeloperoxidase release after stimulation with fMLP. The results showed that the maximum chemiluminescence response was always significantly lower after DTT treatment: blood, 16.68 ±1.89 vs. 2.62 ±0.43 mV, P<0.0001; sputum, 2.96 ±0.30 vs. 1.09 ±0.01 mV, P<0.01; BAL, 25.47 ±0.88 vs. 8.22±0.20 mV, P<0.0001. Both spontaneous and fMLP-induced release of elastase and myeloperoxidase (MPO) was in most cases enhanced after DTT-treatment (P-values range from 0.24 to <0.01). We conclude that the use of DTT to homogenize sputum for dispersion of cells is harmful to cell functions and these cells are hampered for the evaluation of their normal functional characteristics.

3

In vivo effect of orthovanadate on the nitrate reductase activity in cucumber roots

100%

Marciniak J., Buczek J.

Acta Physiologiae Plantarum

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1992

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tom 14

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nr 1

4

Two disulphide bridges are present in juvenile hormone binding protein from Galleria mellonella

100%

Kolodziejczyk R., Dobryszycki P., Ozyhar A., Kochman M.

Acta Biochimica Polonica

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2001

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tom 48

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nr 4

The hemolymph juvenile hormone binding protein (JHBP) from Galleria mellonella contains two disulphide bridges/molecule and no free Cys residues. An alignment of primary structures of other Lepidopteran JHBPs indicates that Cys residues, equivalent to Cys10,17,151,195 in G. mellonella JHBP, may be involved in -S-S- bridge formation.

5

Arabidopsis thaliana Nudix hydrolase AtNUDT7 forms complexes with the regulatory RACK1A protein and gamma subunits of the signal transducing heterotrimeric G protein

80%

Olejnik K., Bucholc M., Anielska-Mazur A., Lipko A., Kujawa M., Modzelan M., Augustyn A., Kraszewska E.

Acta Biochimica Polonica

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2011

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tom 58

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nr 4

Arabidopsis thaliana AtNUDT7 Nudix pyrophosphatase hydrolyzes NADH and ADP-ribose in vitro and is an important factor in the cellular response to diverse biotic and abiotic stresses. Several studies have shown that loss-of-function Atnudt7 mutant plants display many profound phenotypes. However the molecular mechanism of AtNUDT7 function remains elusive. To gain a better understanding of this hydrolase cellular role, proteins interacting with AtNUDT7 were identified. Using AtNUDT7 as a bait in an in vitro binding assay of proteins derived from cultured Arabidopsis cell extracts we identified the regulatory protein RACK1A as an AtNUDT7-interactor. RACK1A-AtNUDT7 interaction was confirmed in a yeast two-hybrid assay and in a pull-down assay and in Bimolecular Fluorescence Complementation (BiFC) analysis of the proteins transiently expressed in Arabidopsis protoplasts. However, no influence of RACK1A on AtNUDT7 hydrolase catalytic activity was observed. In vitro interaction between RACK1A and the AGG1 and AGG2 gamma subunits of the signal transducing heterotrimeric G protein was also detected and confirmed in BiFC assays. Moreover, association between AtNUDT7 and both AGG1 and AGG2 subunits was observed in Arabidopsis protoplasts, although binding of these proteins could not be detected in vitro. Based on the observed interactions we conclude that the AtNUDT7 Nudix hydrolase forms complexes in vitro and in vivo with regulatory proteins involved in signal transduction. Moreover, we provide the initial evidence that both signal transducing gamma subunits bind the regulatory RACK1A protein.

6

Evidence for the involvement of a 66 kDa membrane protein in the synthesis of sterolglucoside in Saccharomyces cerevisiae

80%

Lenart U., Haplova J., Magdolen P., Farkas V., Palamarczyk G.

Acta Biochimica Polonica

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1995

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tom 42

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nr 2

The membrane-bound sterolglucoside synthase from the yeast Saccharomyces cerevisiae has been solubilized by nonionic detergent, Nonidet P-40, Triton X-100, and partially purified by DEAE-cellulose column chromatography and ammonium sulfate fractionation. SDS/PAGE of the purified fraction revealed the presence of two protein bands of molecular mass 66 kDa and 54 kDa. In an attempt to identify further the polypeptide chain of sterolglucoside synthase, the partially purified enzyme was treated with [di-125I]-5-[3-(p-azidosalicylamide)]allyl-UDPglucose, a photoactive analogue of UDPglucose, which is a substrate for this enzyme. Upon photolysis the 12SI-labeled probe was shown to link covalently to the 66kDa protein. The photoinsertion was competed out by the presence of unlabeled UDPglucose thus suggesting that this protein contains substrate binding site for UDPglucose. Since photoinsertion of the probe to protein of 66 kDa correlates with the molecular mass of the protein visualized upon enzyme purification we postulate that the 66 kDa protein is involved in sterolglucoside synthesis in yeast.

7

Biochemical properties of calcyclin - a potential marker of some diseases

80%

Wojda U., Kuznicki J.

Acta Biochimica Polonica

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1993

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tom 40

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nr 1

8

The influence of Cd, Pb, Cu and Ni on NO3 uptake by cucumber seedlings. II. In vitro and in vivo effects of Cd, Cu, Pb and Ni on the plasmalemma ATPase and oxidoreductase from cucumber seedlings roots

70%

Burzynski M., Buczek J.

Acta Physiologiae Plantarum

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1994

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tom 16

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nr 4

Ograniczanie wyników

Influence of 2,5-dichloro-1,4-benzoquinone on jack bean urease activity. Inhibitory effect, total reducing capacity and DPPH radical scavenging activity

Effects of homogenization of induced sputum by dithiothreitol on polymorphonuclear cells

In vivo effect of orthovanadate on the nitrate reductase activity in cucumber roots

Two disulphide bridges are present in juvenile hormone binding protein from Galleria mellonella

Arabidopsis thaliana Nudix hydrolase AtNUDT7 forms complexes with the regulatory RACK1A protein and gamma subunits of the signal transducing heterotrimeric G protein

Evidence for the involvement of a 66 kDa membrane protein in the synthesis of sterolglucoside in Saccharomyces cerevisiae

Biochemical properties of calcyclin - a potential marker of some diseases

The influence of Cd, Pb, Cu and Ni on NO3 uptake by cucumber seedlings. II. In vitro and in vivo effects of Cd, Cu, Pb and Ni on the plasmalemma ATPase and oxidoreductase from cucumber seedlings roots