Department of Biochemistry and Genetics, The Connecticut Agricultural Experiment Station, P. O. 1106, New Haven, Connecticut 06504.
Plant Physiol. 1987 Jun;84(2):450-5. doi: 10.1104/pp.84.2.450.
Leaf extracts of both Nicotiana tabacum and Nicotiana sylvestris contain multiple forms of catalase (H(2)O(2):H(2)O(2) oxidoreductase, EC 1.11.1.6) which are separable at different pH values by chromatofocusing columns. Marked changes in distribution of these catalases occur during seedling development and leaf maturation. The form of catalase eluting first (peak 1) was predominant during early seedling growth and present at all stages of development. Two more acidic forms (peaks 2 and 3) appeared later and comprised 29% of the total activity by 11 days postgermination. Mature leaves of N. tabacum contained peak 1 catalase, but peaks 2 and 3 represented 62% of the total activity. No interconversion of peaks 1, 2, and 3 was detected. The three forms of catalase differed in thermal stability with peak 1 > peak 2 >> peak 3. For N. sylvestris, t((1/2)) at 55 degrees C was 31.5 and 3.0 min for peaks 1 and 3, respectively, and for N. tabacum, t((1/2)) was 41.5 and 3.2 min, respectively. All forms of catalase in tobacco show peroxidatic (measured as ethanol to acetaldehyde conversion) as well as catalatic activities. However, for both Nicotiana species the ratio peroxidatic/catalatic activity is at least 30-fold higher in peak 3 than in peaks 1 and 2. Chromatofocusing of extracts from spinach leaves separated at least four peaks of catalase activity, one of which had a 10-fold higher ratio of peroxidatic/catalatic activity than the others. Short-term growth (5 days) of tobacco seedlings under atmospheric conditions suppressing photorespiration (1% CO(2)/21% O(2)) reduced total catalase activity and caused a decline in peak 1 catalase and a substantial increase in the activity of peaks 2 and 3 relative to air-grown seedlings at the same stage.
烟草和野生烟草的叶提取物均含有多种形式的过氧化氢酶（H2O2:H2O2 氧化还原酶，EC 1.11.1.6），这些酶可在不同 pH 值下通过色谱聚焦柱进行分离。在幼苗发育和叶片成熟过程中，这些过氧化氢酶的分布发生明显变化。在早期幼苗生长过程中，最先洗脱的过氧化氢酶形式（峰 1）占主导地位，并且存在于所有发育阶段。两个更酸性的形式（峰 2 和 3）出现较晚，在发芽后 11 天占总活性的 29%。成熟的烟草叶片含有峰 1 过氧化氢酶，但峰 2 和 3 占总活性的 62%。未检测到峰 1、2 和 3 之间的相互转化。三种形式的过氧化氢酶在热稳定性方面存在差异，峰 1 > 峰 2 > > 峰 3。对于野生烟草，在 55°C 时 t((1/2))分别为 31.5 和 3.0 分钟，而对于烟草，t((1/2))分别为 41.5 和 3.2 分钟。烟草中的所有过氧化氢酶形式均具有过氧化物酶（以乙醇转化为乙醛来衡量）和过氧化氢酶活性。然而，对于两种烟草物种，峰 3 的过氧化物酶/过氧化氢酶活性比峰 1 和 2 至少高 30 倍。菠菜叶提取物的色谱聚焦至少分离出了 4 种过氧化氢酶活性峰，其中一种的过氧化物酶/过氧化氢酶活性比其他峰高 10 倍。在大气条件下（1% CO2/21% O2）下短期生长（5 天）的烟草幼苗会降低总过氧化氢酶活性，并导致峰 1 过氧化氢酶减少，峰 2 和 3 的活性相对于同一阶段在空气中生长的幼苗显著增加。
