Evidently xanthine oxidase is one of the major producers of superoxide anions:    http://www.medscape.com/viewarticle/436774 Yet it is also the route by which uric acid, one of the major anti-oxidants gets produced.  Is there a net benefit to uric acid or not?  Does it always cost a superoxide anion to produce, or does uric acid get recycled somehow so it provides benefit over and over once it has been produced?  If not how can uric acid be a plausible theory for human longevity replacing the role of acorbic acid? It seems like everyday some familiar compound is discovered to be an antioxident, from cholesterol reducing statins to ACE inhibitors and most recently, salicylate:    http://www.medscape.com/viewarticle/434150 More and more it seems to me that the oxident/anti-oxident scale must be as ubiquitous as pH, everything falls on the scale someplace, still I haven't see this explicity presented as a theory.  I've seen the idea that all anti-oxidents are pro-oxidents in some situations.  Is there some good explanation of a unifying theory?  Dr. Proctors writings help some, but the the theory still seems disjoint and less than ubiquitous (sp?) If only some compounds fall on the anti-oxident/oxident scale, why don't we know apriori which ones they are, they seem to come as a surprise?  Shouldn't every compound proposed for medical use also be evaluated to see where it falls on this scale?  Is an anti-oxident often anti-inflammatory side effect in a BP or cholesterol medication an unwanted side effect?  Wouldn't a drug without the side effect be better, which an explicit drug added for direct effect of anti-inflammatory and anti-oxident if that is what is wanted?                    

Evidently xanthine oxidase is one of the major producers of superoxide anions:    http://www.medscape.com/viewarticle/436774 Yet it is also the route by which uric acid, one of the major anti-oxidants gets produced.  Is there a net benefit to uric acid or not?  Does it always cost a superoxide anion to produce, or does uric acid get recycled somehow so it provides benefit over and over once it has been produced?  If not how can uric acid be a plausible theory for human longevity replacing the role of acorbic acid? Data first, explanation later! Of interest: http://groups.google.com/groups?hl=en&lr=&safe=off&selm=69779556.0202... -Michael

Evidently xanthine oxidase is one of the major producers of superoxide anions:    http://www.medscape.com/viewarticle/436774 Yet it is also the route by which uric acid, one of the major anti-oxidants gets produced.  Is there a net benefit to uric acid or not?  Does it always cost a superoxide anion to produce, or does uric acid get recycled somehow so it provides benefit over and over once it has been produced?  If not how can uric acid be a plausible theory for human longevity replacing the role of acorbic acid? Data first, explanation later!        One difference may be that uric acid is a scavenger of some pretty powerful oxidizers such as peroxinitrite,  hydroxyl radical,  etc.,  while superoxide per se is not very reactive and must be converted to (e.g.) one of the above before it becomes destructive.        This requires the presence of something else,  such as nitric oxide produced by (say) iNOS.    All of which provides plenty of opportunity for getting rid of the superoxide before it does something bad.          BTW, ( he says modestly ) I first proposed that Uric acid substitutes for ascorbate in primates over 30 years ago in the journal Nature.   See www.drproctor.com/rev/ascorbicuric.htm .     In a classic example of Dulbecco's law ( the most famous discoverer generally gets the credit,  not the first ),     Bruce Ame's et al's rediscovery a decade later is generally cited <G... Dr P

      One difference may be that uric acid is a scavenger of some pretty powerful oxidizers such as peroxinitrite,  hydroxyl radical,  etc.,  while superoxide per se is not very reactive and must be converted to (e.g.) one of the above before it becomes destructive.       This requires the presence of something else,  such as nitric oxide produced by (say) iNOS.    All of which provides plenty of opportunity for getting rid of the superoxide before it does something bad. So are you theorizing that the protection of provided by allopurinol as described in     http://www.medscape.com/viewarticle/436774 is because the patients involved have some anamolous susceptability to superoxide anions, that outweighs the benefits of uric acid in their cases?                

Data first, explanation later! Of interest: http://groups.google.com/groups?hl=en&lr=&safe=off&selm=69779556.0202... -Michael I had seen this discussion, which is why I found the news so paradoxical.  Does the full text of   Chung HY, Yu BP.   Significance of hepatic xanthine oxidase and uric acid in aged and   dietary restricted rats.   J Am Aging Assoc. 2000 Jul; 23(3): 123-8. have a discussion of xanthine oxidase production of superoxide anion and why the benefits of uric acid apparently outweigh it?   Is this article available on the internet?