Peroxide Production and Peroxidase Activity of Sulfathiazole Sensitive and Resistant Strain of Streptococcus mitis . ∗

Summary

Aerobically grown sulfathiazole resistant cells of S. mitts produced a much more active peroxidase than the parent sensitive cells. H₂O₂ was produced by both the resistant and sensitive cells but was destroyed in the resistant cell culture after the first few hours of growth. Suspensions of anaerobically grown resistant cells had no peroxidase activity until a heat stable extract of the aerobically grown cells was added. The peroxidase activity was not appreciably changed by variation of pH between 6 and 8, change in temperature for growth or for incubation with H₂O₂, nor by the presence of sulfathiazole, penicillin or dihydrostreptomycin.