Ferulic acid: a substrate for two isoperoxidases from Nicotiana tabacum tissue cultures |
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| Authors: | Jerry W Pickering Bernard L Powell Simon H Wender Eddie C Smith |
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| Institution: | Department of Chemistry, Biochemistry Division, University of Oklahoma, Norman, OK 73069, U.S.A. |
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| Abstract: | An anodic isoperoxidase (A2) from tobacco tissue culture W-38 and a cathodic isoperoxidase (C4) from tobacco tissue suspension culture WR-132 have been separated and characterized. Both isoperoxidases catalysed oxidation of ferulic acid in the presence of H2O2. When the reaction mixture was subjected to TLC, ferulic acid was found to have been converted to an unknown compound which, after treatment with ammonia, fluoresces green in UV light. Both the isoperoxidases A2 and C4 appear to follow simple Michaelis-Menten kinetics with respect to guaiacol as the substrate. The Kms for guaiacol are 4 and 4·5 mM for isoperoxidases C4 and A2, respectively. The pH optimum for both enzymes is about 6·0. The effect of various phenolic and related compounds on the activity of each isoperoxidase is reported and discussed. |
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| Keywords: | Solanaceae tobacco isoperoxidase |
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