oxidation of methionine , 4- ( methylthio ) -2-oxobutyric acid ( kmb ) , or 1-aminocyclopropane carbonic acid ( acc ) are indicator reactions for activated oxygen species such as singlet oxygen ( 1o2 ) , oh.-radical like oxidants , superoxide anion ( o2.- ) , hydrogen peroxide ( h2o2 ) or activated hemo-iron complexes like peroxidase- or catalase- '' '' compound i '' '' .
C0030011
oxidation
C0027021
peroxidase