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Kinetic independenc...
Kinetic independence of the subunits of cytosolic glutathione transferase from the rat
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- Danielson, U Helena (author)
- Uppsala universitet,Biokemi
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Mannervik, Bengt (author)
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(creator_code:org_t)
- 1985
- 1985
- English.
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In: Biochemical Journal. - 0264-6021 .- 1470-8728. ; 231:2, s. 263-267
- Related links:
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https://urn.kb.se/re...
Abstract
Subject headings
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- The steady-state kinetics of the dimeric glutathione transferases deviate from Michaelis-Menten kinetics, but have hyperbolic binding isotherms for substrates and products of the enzymic reaction. The possibility of subunit interactions during catalysis as an explanation for the rate behaviour was investigated by use of rat isoenzymes composed of subunits 1, 2, 3 and 4, which have distinct substrate specificities. The kinetic parameter kcat./Km was determined with 1-chloro-2,4-dinitrobenzene, 4-hydroxyalk-2-enals, ethacrynic acid and trans-4-phenylbut-3-en-2-one as electrophilic substrates for six isoenzymes: rat glutathione transferases 1-1, 1-2, 2-2, 3-3, 3-4 and 4-4. It was found that the kcat./Km values for the heterodimeric transferases 1-2 and 3-4 could be predicted from the kcat./Km values of the corresponding homodimers. Likewise, the initial velocities determined with transferases 3-3, 3-4 and 4-4 at different degrees of saturation with glutathione and 1-chloro-2,4-dinitrobenzene demonstrated that the kinetic properties of the subunits are additive. These results show that the subunits of glutathione transferase are kinetically independent.
Subject headings
- NATURVETENSKAP -- Kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences (hsv//eng)
Keyword
- Chemistry
- Kemi
Publication and Content Type
- ref (subject category)
- art (subject category)
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