The activities of antioxidant enzymes in rumen bacteria Streptococcus bovis and Selenomonas ruminantium

The activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx) and glutathione reductase (GR) in the rumen facultative anaerobic bacteria Streptococcus bovis 4/1 and the strictly anaerobic bacteria Selenomonas ruminantium E 32 were determined. In S. bovis a relatively high superoxide dismutase was found. The activities were similar under aerobic (189.60 +/- 1.04 mU/mg prot.) or anaerobic (196.80 +/- 29.10 mU/mg prot.) conditions. SOD activity was only Mn SOD. For GSHPx there was not a significant difference between the aerobic (3.11 +/- 0.09 mU/mg prot.) and anaerobic (3.75 +/- 0.58 mU/mg prot.) activities. The activity of GR was NADPH specific and was similar under both the aerobic and anaerobic conditions (61.53 +/- 6.69 mU/mg prot.; 53.06 +/- 5.53 mU/mg prot.). S. ruminantium showed no SOD, CAT and GSHPX-H(2)O(2) activities. The specific activity of NADPH GR was relatively high (27.63 +/- 2.19 mU/mg prot.). The enzymatic activities (SOD, GSHPx, GR) were affected by the growth phase of S. bovis and were the highest at the stationary phase.