Development of Microbodies in Sunflower Cotyledons and Castor Bean Endosperm during Germination.
Development of Microbodies in Sunflower Cotyledons and Castor Bean Endosperm during Germination.
复制标题
向日葵子叶和蓖麻子胚乳萌发过程中微生物的发育。
DOI：
10.1104/pp.48.5.566
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发表时间：
1971
期刊：
影响因子：
7.4
通讯作者：
N. Tolbert
中科院分区：
文献类型：
--
作者：
C. Schnarrenberger;A. Oeser;N. Tolbert
在向日葵幼苗子叶中，乙氧化酶和过氧化物酶体酶在萌发过程中表现出不同的发育速率。异柠檬酸裂解酶（glyoxysomal marker酶）的总活性在前3天迅速升高，到第9天下降89%。暴露在光线下只略微加速了这种下降。在蔗糖密度梯度下，微体组分中糖酶体酶（苹果酸合成酶、异柠檬酸裂解酶、柠檬酸合成酶和乌头酸酶）的比活性在第2 ~ 4天增加了约2 ~ 3倍，此后在光照和黑暗条件下基本保持不变。萌发前4天，过氧化物酶总活性在黑暗条件下缓慢升高，此后在黑暗条件下保持恒定水平或在光照条件下24小时增加2倍。在黑暗条件下，分离的微体部分的乙醇酸氧化酶、羟丙酮酸还原酶和丝氨酸-乙醛酸氨基转移酶的比活性在第2天和第4天增加了约10倍，然后在光照条件下再增加48小时后保持不变或再次增加10倍。常见的微体标记物过氧化氢酶的总活性与异柠檬酸裂解酶相似，但在第9天仅下降72%。两种微体系统共有的酶（过氧化氢酶、苹果酸脱氢酶和天冬氨酸转氨酶）的比活性比其他酶高10- 1000倍。有人提出苹果酸和天冬氨酸可能参与氢在微体和其他细胞部位之间的转运。蓖麻胚乳和向日葵子叶的微体中谷氨酸-乙醛转氨酶非常活跃。这种转氨酶的特定活性在黑暗环境中与乙醛酶类似，但在光线下进一步增加，过氧化物酶也是如此。在黑暗中萌发5 d的蓖麻胚乳微体部分含有比活性相近的乙氧化酶和过氧化物酶体酶。在葵花子叶蔗糖梯度上，与微体部分相邻的是密度稍低的病质体和密度相近或较高的蛋白质体。它们在微体中的存在导致人为的低比活性。
In cotyledons of sunflower seedlings glyoxysomal and peroxisomal enzymes exhibit different rates of development during germination. The total activity of isocitrate lyase, a glyoxysomal marker enzyme, rapidly increased during the first 3 days, and then decreased 89% by day 9. Exposure to light accelerated this decrease only slightly. The specific activity of glyoxysomal enzymes (malate synthetase, isocitrate lyase, citrate synthetase, and aconitase) in the microbody fraction from sucrose density gradients increased between days 2 and 4 about 2- to 3-fold, and thereafter it remained about constant in light or darkness.Total activity of the peroxisomal enzymes increased slowly in the dark during the first 4 days of germination and thereafter remained at a constant level of activity in the dark or increased 2-fold in 24 hours of light. The specific activties of glycolate oxidase, hydroxypyruvate reductase, and serine-glyoxylate aminotransferase in the isolated microbody fraction increased about 10-fold between days 2 and 4 in the dark and then remained constant or increased again 10-fold after an additional 48 hours in the light.The total activity of the common microbody marker, catalase, developed similarly to isocitrate lyase, but decreased only 72% by day 9. The specific activities of enzymes (catalase, malate dehydrogenase, and aspartate aminotransferase) common to both microbody systems were 10- to 1000-fold greater than those of other enzymes. It is proposed that malate and aspartate may be involved in hydrogen transport between microbodies and other cellular sites.Glutamate-glyoxylate aminotransferase was very active in microbodies from castor bean endosperm and sunflower cotyledons. The specific activity of this aminotransferase developed similarly to glyoxysomal enzymes in the dark but further increased in the light, as did peroxisomal enzymes.The microbody fraction of castor bean endosperm germinated in the dark for 5 days contained both glyoxysomal and peroxisomal enzymes of similar specific activity.Adjacent to the microbody fraction on sucrose gradients from sunflower cotyledons were etioplasts at slightly lower densities and protein bodies at similar and higher densities. Their presence in the microbody fractions resulted in artificially low specific activities.