The decomposition of peroxydisulfate to sulfate radical ions was taken to be a rapid preequilibrium, and was postulated to be followed by the rate-determining reaction of a sulfate radical ion with MG to produce a radical intermediate, I.
Source: wiktionary
In cases involving multiple preequilibria (e.g., multiple substrates, induced conformational change), K.,, reveals little about each of these steps individually. In the case of allosteric interaction, characteristic kinetic behavior is...
Source: wiktionary