Polyamine oxidase in oat leaves: a cell wall-localized enzyme.
Polyamine oxidase in oat leaves: a cell wall-localized enzyme.
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燕麦叶中的多胺氧化酶：一种细胞壁定位酶。
DOI：
10.1104/pp.68.2.494
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发表时间：
1981
期刊：
影响因子：
7.4
通讯作者：
Arthur W. Galston
中科院分区：
文献类型：
--
作者：
R. Kaur;Hector E. Flores;Arthur W. Galston
研究了燕麦幼苗叶片和原生质体中多胺氧化酶（PAO; EC 1.5.3.3）的定位和活性。该酶以精胺为底物时活性最高;亚精胺也被氧化，但腐胺和尸胺不受该酶的影响。用纤维素酶在高渗培养基中消化叶片后分离的原生质体没有PAO活性，约80%的叶片PAO活性可以在细胞壁碎片中找到。组织化学定位实验表明，强烈的PAO活性在保卫细胞和维管元件，其壁不被纤维素酶消化。当原生质体培养在适合细胞壁再生的培养基中时，随着纤维素壁的发育，可以检测到PAO活性。由于施用精胺和亚精胺可以防止离体叶片的衰老，因此研究了叶片衰老过程中PAO的活性。PAO的比活性随贴附叶龄的增加而下降，随离体叶片在黑暗中衰老的增加而下降。这种酶活性的下降，这是平行的叶绿素和蛋白质含量的减少，叶片衰老的措施，表明该酶不参与燕麦叶片衰老的控制。
The localization and activity of polyamine oxidase (PAO; EC 1.5.3.3), was investigated in leaves and protoplasts of oat seedlings. Activity of the enzyme is highest with spermine as substrate; spermidine is also oxidized, but putrescine and cadaverine are unaffected by the enzyme. Protoplasts isolated following digestion of leaves with cellulase in hypertonic osmoticum showed no PAO activity, and about 80% of the total leaf PAO activity could be accounted for in the cell wall debris. Histochemical localization experiments showed intense PAO activity in guard cells and in vascular elements whose walls are not digested by cellulase. When protoplasts were cultured in a medium suitable for regeneration of cell wall, PAO activity could be detected as the cellulose wall developed. Thus, PAO appears to be localized in cell walls.Since applied spermine and spermidine prevent senescence of detached leaves, PAO activity was investigated during leaf senescence. The specific activity of PAO declines with increasing age of attached leaves and with increasing senescence of excised leaves incubated in darkness. This decline in enzyme activity, which parallels the decreases in chlorophyll and protein content used as measures of leaf senescence, suggests that the enzyme is not involved in the control of senescence of oat leaves.