Effect of Enzymically Generated Electronic-Excited Species on Membrane-Bound Na+,K+-ATPase

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Title:Effect of Enzymically Generated Electronic-Excited Species on Membrane-Bound Na+,K+-ATPase
Creators:
Obšil, Tomáš
Amler, Evžen
Pavlíček, Zdeněk
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 61, 1, pp. 160-170
Uncontrolled Keywords:Fluorescence, Electronic-excited species, Na<sup>+</sup>,K<sup>+</sup>-ATPase

Abstract

The effect of electronic-excited species generated by systems 2-methylpropanal (MPAL) plus horse-radish peroxidase (HRP) and glyceraldehyde (GCA) plus HRP on Na<sup>+</sup>,K<sup>+</sup>-ATPase activity was investigated. For the system MPAL-HRP (which generates triplet acetone) Na<sup>+</sup>,K<sup>+</sup>-ATPase activity, the concentration of malondialdehyde, the membrane lateral pressure and the collisional quenching of protein tryptophan residues by NaI were determined. The enzyme activity decreased by 70% during the incubation. Lipid peroxidation products were increased to a steady state level from 5.5 ± 0.5 to 22.6 ± 0.7 nmol malondialdehyde mg<sup>-1</sup> protein after 60 min. The membrane lateral pressure was increased from 83.6 ± 0.4 to 90 ± 0.9 mN m<sup>-1</sup>. In peroxidized membranes, the fluorescence intensity of tryptophan residues was decreased and the fluorescence intensity of bityrosine adducts was increased. Changes of conformation of Na<sup>+</sup>,K<sup>+</sup>-ATPase were observed by the collisional quenching of protein tryptophan residues by NaI. For the system GCA-HRP the Na<sup>+</sup>,K<sup>+</sup>-ATPase activity decreased by 20% after incubation with GCA and by 30% with GCA-HRP. Changes of conformation of Na<sup>+</sup>,K<sup>+</sup>-ATPase were detected both after the incubation with GCA and GCA-HRP. These results demonstrate that electronic-excited species inhibit the activity of membrane-bound Na<sup>+</sup>,K<sup>+</sup>-ATPase both by an increase of membrane lateral pressure of the lipid microenvironment of the ATPase molecules and by a direct effect of oxidation of protein residues, i.e. tryptophan, tyrosine.

Title:Effect of Enzymically Generated Electronic-Excited Species on Membrane-Bound Na+,K+-ATPase
Creators:
Obšil, Tomáš
Amler, Evžen
Pavlíček, Zdeněk
Uncontrolled Keywords:Fluorescence, Electronic-excited species, Na<sup>+</sup>,K<sup>+</sup>-ATPase
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:61
Number:1
Page Range:pp. 160-170
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19960160UNSPECIFIED
ID Code:924
Item Type:Article
Deposited On:06 Feb 2009 17:05
Last Modified:06 Feb 2009 16:05

Citation

Obšil, Tomáš; Amler, Evžen; Pavlíček, Zdeněk (1996) Effect of Enzymically Generated Electronic-Excited Species on Membrane-Bound Na+,K+-ATPase. Collection of Czechoslovak Chemical Communications, 61 (1). pp. 160-170. ISSN 0010-0765

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