Published online by Cambridge University Press: 01 June 2009
The inactivation of lactoperoxidase (LP) by cultures of Group N streptococci was originally reported by Kiermeier & Kayser (1960). However, Pickering, Oram & Reiter (1962) found that incubation of Streptococcus cremoris 803 with LP did not completely inactivate the enzyme, but only modified its activity with certain substrates. This observation was subsequently confirmed by Kiermeier & Lechner (1966, 1967). In the present investigation, several strains of Group N streptococci were found to modify LP in such a way as to cause total or partial loss of enzymic activity with guaiacol. This loss of LP activity was found to be a consequence of the production of hydrogen peroxide by these organisms.