Activation of corn glutathione S-transferase enzymes by coumaric acid and 7-hydroxycoumarin
1993
Dean, J.V. | Machota, J.H.
The corn glutathione S-transferase (GST) enzyme(s) that is active with trans-cinnamic acid appears to require an endogenous low Mr activator(s) since 59% of this GST activity is lost following desalting of crude extracts. Desalting had very little effect on the corn GST enzyme(s) that is active with 1-chloro-2,4-dinitrobenzene (CDNB). The in vitro activity of the GST (trans-cinnamic acid) activity purified through anion-exchange chromatography, was increased 2.6- and 6.4-fold by the addition of 50 micromolar p-coumaric acid and 7-hydroxycoumarin, respectively. In contrast, p-coumaric acid and 7-hydroxycoumarin did not activate the GST (CDNB) activity. During the purification of GST enzymes from etiolated corn shoots, only one peak of GST (trans-cinnamic acid) activity was detected in the anion-exchange chromatography elution profile, however, when p-coumaric acid or 7-hydroxycoumarin were added to the in vitro assays, the initial peak of GST activity was enhanced and several additional peaks of GST (trans-cinnamic acid) activity were observed.
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