In our recent contribution [1]we questioned the role of dehydroascorbate (DHA) and DHA reductase as reliable indicators of oxidative stress in plants. Several lines of evidence were presented to substantiate that the measurement of DHA pools and DHA reductase activity in crude plant extracts is falsified by technical problems and by the fact that plant cells contain several redox-active proteins with unspecific DHA-reducing activity. We discussed whether the disproportionation of monodehydroascorbate (MDHA) leads to an appreciable formation of DHA in plant cells considering the known chemical and biochemical data of MDHA reductase and other MDHA-reducing components. Moreover, we questioned whether plant cells necessarily require a specific DHA reductase and concluded that they probably do not possess a specific DHA reductase at all. It is not surprising that these statements raise a dispute. Unfortunately, Foyer and Mullineaux [2]in their commentary try to counter our conclusions not by new facts but by remote arguments.
Dehydroascorbate reduction: The phantom remaining
De Tullio M.;
1998-01-01
Abstract
In our recent contribution [1]we questioned the role of dehydroascorbate (DHA) and DHA reductase as reliable indicators of oxidative stress in plants. Several lines of evidence were presented to substantiate that the measurement of DHA pools and DHA reductase activity in crude plant extracts is falsified by technical problems and by the fact that plant cells contain several redox-active proteins with unspecific DHA-reducing activity. We discussed whether the disproportionation of monodehydroascorbate (MDHA) leads to an appreciable formation of DHA in plant cells considering the known chemical and biochemical data of MDHA reductase and other MDHA-reducing components. Moreover, we questioned whether plant cells necessarily require a specific DHA reductase and concluded that they probably do not possess a specific DHA reductase at all. It is not surprising that these statements raise a dispute. Unfortunately, Foyer and Mullineaux [2]in their commentary try to counter our conclusions not by new facts but by remote arguments.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
