Oxidative degradation of pyruvate formate-lyase

The reaction mechanisms of oxidative degradation of the anaerobic radical e nzyme pyruvate formatelyase (PFL) have been examined at the theoretical hyb rid Hartree-Fock/density functional theory level B3-LYP. It is concluded th at the most likely scenario involves Oz addition at the glycyl radical site , followed by H-. abstraction/transfer from C419 and subsequent rearrangeme nts to generate an cr-hydroxyglycine and the sulfinyl radical R-SO., observ ed by EPR spectroscopy. In addition, the present model accounts for alterna tive fragmentations observed in wild-type PFL, and the formation and degrad ation of Gly-O-O-. in the absence of C419 (as observed in C419A and C419AC4 18A mutants).