Figure 18. The relationship between the rate of catalyst-mediated inactivation and/or cleavage on the catalyst reduction potential depended on both the nature of the target (nucleic acid vs protein) and reactivity with the principle redox coreactants (17, 18). A, Cleavage of HIV Rev response element (RRE) RNA by M-chelate-Rev catalysts. B, Inactivation of sACE-1 by M-chelate-lisinopril catalysts. For RNA and DNA cleavage, rates were highest for reduction potentials (low potential region) between those of H₂O₂/hydroxyl radical (E° = +380 mV) and ascorbyl radical/ascorbate (E° = -66 mV), shown by the dashed lines, for which multiple turnovers (and generation of reactive oxygen species) were thermodynamically favored. For inactivation of the enzyme sACE-1, rates were highest for M-chelates with reduction potentials near 1000 mV (high region).