... selenocysteine in mammalGPXs. The selenocysteine residue is important for thecatalytic activity of GPX as replacement of selenocysteine bycysteine greatly reduces the activity of the enzyme [12].According ... X-100 (peroxide free), t-butyl hydroper-oxide, cumene hydroperoxide, hydrogen peroxide, linoleicacid,L-a-phosphatidylcholine dilinoleoyl and soybeanlipoxidase (type IV) were purchased from ... daylight at 60 lmolÆm)2Æs)1,photosynthetically active radiation provided by 40-W whitedaylight tubes (Mazda LDL, TF 40), 23 ± 1 °C(day )and 19 ± 1 °C (night), 60 ± 10% relative humidity....