Re: AZT oxidation 2 September 2004
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Jean Umber,
Agrégé de chimie
France

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Re: Re: AZT oxidation

We don't talk here in common understanding, we must be chemically correct.

We must here talk from redox pairs.

For instance we have here the redox pairs AZT/d4T, AZT/AMT,.. RSO2(-)/RSH, RSO3(-)/RSH,... the right member is the oxidized species, the left is the reduced species.

It is significant to know the redox potential (or standard potential) of each pair.

For instance, the value of the standard potential from HN3/NH4(+)is 0,695 V (in french convention), and the one from SO3(2-)/H2S is 0,35 V, (E[SO4(2 -)/H2S] = 0,3V).

Therefore HN3 oxidizes H2S in sulfite (or sulfate...). Unfortunately, I have not found those from RN3/RNH3(+) or RSO3(-)/RSH But, although we must consider the modification of hydrogen bonding, the substitution of H by R does change only a little the gap between these standard potentials.

Thermodynamically, the azides react without any problems with thiols. The kinetics at 37° is slow. Therefore these reactions are far from complete.

I apologize because I have not read the full text from Becher & al. AZTTP is actually found in PBMC (about 10 nmol in all the PBMC of the blood). It should be interesting to know the concentration of thymidineTP in the PBMC. But which is the reducing agent which performs the formation of d4T ? Why do you not accept the intervention of thiols? It should be also interesting to measure out the concentration of 3TCTP.

Lamivudine is a 1,3-oxathiolane, whose hydrolysis kinetics are quite fast at pH=1 and room temperature into glycolic aldehyde and 1-cytosyl 2- mercaptoéthanol. Have you data relating to this phenomenon ?

Competing interests: None declared