Water Technology Centre, Indian Agricultural Research Institute, New Delhi, India.
Biochem Biophys Res Commun. 2011 Sep 9;412(4):522-5. doi: 10.1016/j.bbrc.2011.06.179. Epub 2011 Jul 5.
Thermal stability of antioxidant defense enzymes superoxide dismutase (SOD, EC 1.15.1.1) and ascorbate peroxidase (APX, EC 1.11.1.11) was studied in chloroplasts and mitochondria of leaf and inflorescence in heat adaptive weed Chenopodium album. Leaf samples were taken in March (31°C/14°C) and young inflorescence (INF) was sampled at flowering in April (40°C/21°C). Leaf and INF chloroplast and mitochondrial fractions were subjected to elevated temperatures in vitro (5-100°C) for 30'. SOD and APX showed activity even after boiling treatment in both chloroplast and mitochondria of leaf and INF. SOD was more heat stable than APX in both chloroplasts and mitochondria in both the tissues. Chloroplast contained more heat stable SOD and APX isozymes than mitochondria in both leaf and INF. To the best of our knowledge this is the first report showing presence of thermostable APX isozymes (100°C for 30') in chloroplasts and mitochondria in C. album. Heat stable isozymes of SOD and APX in chloroplasts and mitochondria in leaves and inflorescence may contribute to heat tolerance in C. album.
抗氧化防御酶超氧化物歧化酶（SOD，EC 1.15.1.1）和抗坏血酸过氧化物酶（APX，EC 1.11.1.11）在热适应杂草藜（Chenopodium album）的叶绿体和线粒体中的热稳定性进行了研究。叶片样本于 3 月（31°C/14°C）采集，4 月（40°C/21°C）开花时采集幼嫩花序（INF）。将叶片和 INF 的叶绿体和线粒体部分在体外（5-100°C）下加热 30'。SOD 和 APX 在叶片和 INF 的叶绿体和线粒体中即使经过煮沸处理仍具有活性。在两种组织的叶绿体和线粒体中，SOD 比 APX 更耐热。在叶片和 INF 中，叶绿体比线粒体含有更多热稳定的 SOD 和 APX 同工酶。据我们所知，这是首次报道在藜的叶绿体和线粒体中存在热稳定的 APX 同工酶（30'，100°C）。叶绿体和线粒体中 SOD 和 APX 的热稳定同工酶可能有助于藜的耐热性。
