Reid P D, Strong H G
Department of Biological Sciences, Smith College, Northampton, Massachusetts 01060.
Plant Physiol. 1974 May;53(5):732-7. doi: 10.1104/pp.53.5.732.
Cellulase (beta-1, 4-glucan-glucanohydrolase EC 3.2.1.4) activity in the abscission zone of red kidney bean (Phaseolus vulgaris) was previously shown to exist in at least two different molecular forms. The form of the enzyme which has an isoelectric point of 4.5 is present in both abscising and nonabscising tissue and requires grinding for extraction. Another form of the enzyme which has an isoelectric point of 9.5 is present only in tissue in which the abscission process has been induced. Further, much of this form of cellulase can be removed from the tissue by vacuum infiltration with buffer. Time course studies indicate that while the increase in measurable cellulase activity in tissue which is actively undergoing abscission was due primarily to the appearance of cellulase 9.5, this form of the enzyme cannot be removed by vacuum infiltration until after the breakstrength of the abscission zone has decreased nearly to zero. The intracellular localization of these two forms of cellulase is discussed.
先前研究表明，红芸豆（菜豆属）脱落区的纤维素酶（β-1,4-葡聚糖-葡聚糖水解酶，EC 3.2.1.4）活性至少以两种不同分子形式存在。等电点为4.5的酶形式同时存在于正在脱落和未脱落的组织中，提取时需要研磨。另一种等电点为9.5的酶形式仅存在于已诱导脱落过程的组织中。此外，通过用缓冲液真空渗透可从组织中去除大部分这种形式的纤维素酶。时间进程研究表明，虽然正在积极进行脱落的组织中可测量的纤维素酶活性增加主要归因于纤维素酶9.5的出现，但直到脱落区的断裂强度几乎降至零后，这种酶形式才能通过真空渗透去除。本文还讨论了这两种形式纤维素酶在细胞内的定位。
