Institute of Biochemistry, University of Warsaw, Al. Zwirki i Wigury 93, PL 02-089, Warszawa, Poland.
Planta. 1978 Jan;144(1):49-56. doi: 10.1007/BF00385006.
The levels of both tightly and loosely bound Mn in chloroplasts from fresh, cold and dark stored as well as illuminated leaves of Lycopersicon esculentum Mill. were studied in relation to Hill reaction activity. The tightly bound Mn pool represents one third of the total Mn content in chloroplasts isolated from the fresh leaves, and its level does not change following cold storage and illumination of leaves. Upon cold and dark storage of leaves the loss from the chloroplasts of about 40%-50% of the total amount of Mn is accompanied by an almost complete inactivation of the Hill reactions, as studied with water as an electron donor, as well as by the appearance of an EPR signal characteristic of free Mn(2+) ions. Following illumination of such leaves, the restroration of Hill reaction activity is accompanied by an increase in the total Mn content in chloroplasts of up to 70%-80% of the Mn level measured in the fresh leaves and by disappearance of the EPR signal. In contrast, aging in the cold of isolated chloroplasts does not affect their Mn content. The addition of manganese does not result in the restoration of Hill reaction activity in chloroplasts from cold stored leaves but causes a restoration of this activity inhibited by linolenic acid. The data suggest that the loosely bound Mn pool (extractable with Tris) can be differentiated into two fractions: (1) one functionally inactive in electron transport and (2) one responsible for restoration of Hill reaction activity. Mn of the latter fraction (about 45% of the total Mn content) probably originates from the free Mn ions present in the interior of the chloroplasts following the cold and dark storage of leaves and from Mn reincorporated into chloroplasts from the cytoplasm. Incorporation of Mn from both these sources into thylakoid membrane to form a functionally active, loosely bound Mn pool proceeds during the illumination of leaves and results in the restoration of Hill reaction activity inhibited following the storage of leaves in dark and cold.
研究了与希尔反应活性有关的新鲜、冷藏和黑暗贮藏以及光照的番茄叶叶绿体中紧密结合和松散结合的 Mn 水平。从新鲜叶片分离的叶绿体中，紧密结合的 Mn 池代表总 Mn 含量的三分之一，其水平在叶片冷藏和光照后不会改变。叶片冷藏和黑暗贮藏时，叶绿体中约 40%-50%的总 Mn 损失伴随着希尔反应的几乎完全失活，这是用水作为电子供体研究的，以及出现特征自由 Mn(2+)离子的 EPR 信号。在这种叶片光照后，Hill 反应活性的恢复伴随着叶绿体中总 Mn 含量增加到新鲜叶片测量值的 70%-80%，以及 EPR 信号的消失。相比之下，冷藏分离的叶绿体的老化不会影响其 Mn 含量。添加锰不会导致冷藏叶片叶绿体的希尔反应活性恢复，但会导致由亚麻酸抑制的希尔反应活性恢复。数据表明，松散结合的 Mn 池（用 Tris 提取）可分为两部分：（1）一种在电子传递中不起作用；（2）一种负责恢复希尔反应活性。后一部分 Mn（约占总 Mn 含量的 45%）可能来自于叶片冷藏和黑暗贮藏后叶绿体内部存在的自由 Mn 离子，以及从细胞质重新掺入叶绿体的 Mn。来自这两个来源的 Mn 掺入类囊体膜以形成功能活跃的松散结合的 Mn 池，在叶片光照期间进行，导致在叶片黑暗和冷藏贮藏后抑制的希尔反应活性恢复。
