The oxidation of hypersensitive radical probes by chloroperoxidase from Caldariomyces fumago (CPO) was studied in an attempt to “time” a putative radical intermediate. Oxidation of (trans-2-phenylcyclopropyl) methane, previously studied by Zaks and Dodds [Zaks, A., and Dodds, DR (1995) J. Am. Chem. Soc. 115, 10419-10424] was reinvestigated. Unrearranged oxidation products were found as previously reported, and control ...