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<---- Begin Forwarded Message ----> Date: Wed, 8 Nov 1995 22:37:38 -1000 From: Anthony Montgomery <amontgom@ha*.ed*> To: techdiver <techdiver@terra.net> Here's a biochemically question: Today I learn how O2 toxicity starts. It begins toward the end of the electron transport chain when O2 is reduced into H2O. Ctyochrome oxidase binds O2 in an Fe-Cu complex allowing the O2 to accept four electrons to produce two molecules of H2O. This is the normal pathway, but if O2 does not accept four complete electrons, then a Superoxide anion is produced. This is a very destructive compound and is the begining of O2 toxicity. The Superoxide anion is not produced under normal circumstances (except for small amounts) and I assume it is produced when the conditions are met to cause O2 toxicity such as extended periods of pure O2 or high ppO2. What is the direct chemical interaction that causes the Superoxide anion to be produced? Is it caused by the bombardment of O2 molecules in the reaction so the electrons that would go into the reduction of O2 actual starts binding to the O2 molecules yielding the Superoxide anion? Also, I assume the Superoxide anion interfers with the neural pathways and this is what causes the actual symptoms of O2 toxicity. Is there a biochemical/physoilogical explaination for this as well? Another question: I discussed this with my prof. and he mentioned that the Superoxide anion has another side effect. This molecule can alter the Guanine base on DNA;therfore, when this base is replicated it produces the wrong base pair match. This in turn can create mutations and possibly long term, irreversible side effects. Are there any known cases of this happening from diving high pp O2s? This has been a problem among athletes. Any explanations for these reactions would be greatly appreciated!! Any flames on this subject are also welcome!! Aloha Tony ANTHONY MONTGOMERY Marine Option Program Waikiki Aquarium 1000 Pope Road MSB #203 2777 Kalakaua Ave Honolulu, Hawaii 96822 Honolulu, Hawaii 96815 Fax: (808) 956-2417 Fax: (808) 923-1771 Phone: (808) 956-6000 Phone: (808) 923-9741 -- Send mail for the `techdiver' mailing list to `techdiver@terra.net'. Send subscription/archive requests to `techdiver-request@terra.net'. <---- End Forwarded Message ---->
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