,P d k > 3000 M -1 •s -1 ) to no longer interfere on the kinetics (solid plots in graph D of Figure ). This apparent inconsistency suggests that in parallel to the H2O2 deprotection of the intermediate P2, additional fast reactions contribute to an accelerated deprotection of P2. We emitted the hypothesis that it could be due to the autoxidation of P2 (reaction S8), which instead of a two-electron transfer reaction, as we have at first assumed, occurs through a one-electron transfer between O2 and P2 with the concomitant production of radical species (notably O2 •- , which by dismutation can produce H2O2 for additional deprotection of both P3 and intermediate P2). One can then conceive that these radical species can either directly or indirectly further contribute to the accelerated deprotection of the intermediate P2. We will come back later on this specific point. It is to note that the value of