In my recent research, SOD, MDA and GSH showed an increase in enzymatic activity due to heavy metal stress. But CAT (catalase) showed a decrease in activity.
What are the possible reasons? The literature says CAT concentration increases with heavy metal stress. A few scientists supported my results of lowering of CAT activity.
Is there any literature present regarding these results?
Hi, you have to fix the time of exposure, to can analyse your data correctly, first thing to bring in mind that Catalase and superoxide dismutase SOD, function in cascading to eliminate the toxicity of ROS , normally the activity of each one should follow the general expression activity of the other one, but sometimes this phenomenon dosen't happened, because of a loss or decreases in energy, as you know those two enzymes are oxygen dependent functionalized (energitic phenomenon that depend on ATP) for that the time of exposure and the conditions are very important for anlysing data, i'll send you some papers since i find them, soryy i'm very busy at the moment for that i couldn't send them, Regards.
thank you Younes for your helpful ans. yes I'll appreciate papers from you I hope they'll add more knowledge.
Regards.
WAQAS AZEEM
I don't entirely agree with Younes. The only enzyme responsible for detoxifying hydrogen peroxide is the selenoenzyme, glutathione peroxidase (GSH-Px). While in theory catalase can detoxify hydrogen peroxide, this action occurs at millimolar concentrations of hydrogen peroxide (present only in peroxisomes) whereas GSH-Px detoxifies hydrogen peroxide at micro molar concentrations. Furthermore, acatalasemia is not associated with any serious disease in animal models or in humans. SOD dissimulates the superoxide free radical to hydrogen peroxide so its role in vivo is limited because in the absence of GSH-Px, animals with greater SOD activity would die. Please see our several papers on this topic.
Respected Sir Ijaz,,
I also appreciate your answer. But what literature says supporting younes, & sir you you have used a term Animal...! are there chances that mechanism of GSH detoxification which occured in animals is quite different in plant..? There might be other factors that are involved and differ from your opinion...!? there is still ambiguity regarding acceptance of opinion and suggestion and I still feel uncertainty in defending my results. Sir can you give me some literature supporting your opinion.
REGARDS.
WAQAS AZEEM
Hi, i'm absolutely disagree with sir Ijaz, i red many papers suppoting my point of view also , what is the role of Catalse??? and SOD??? i'm really very busy now to send those papers, but i promise you that i'll send them soon,
In most studies in plant species catalase activity decreases with meta l stress some find initial increase followed by decline this Probably due to an oxidation of the native enzyme since it is an iron containing enzyme other possible way might be up regulated at transcriptional level which one is working this might be depend upon metal concentrations an the length of exposure time. With my best wishes
Upregulation of the protein content of an enzyme can sometimes be a meaningless metric. Since enzymes are catalysts, we are primarily interested in their activity which, by definition, is thousands of millions of reactions per enzyme moiety and therefore, increased or decreased expression of the protein moiety may be of little biological consequence.
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