Derepression and Repression of Lysine-sensitive Aspartokinase during in Vitro Culture of Carrot Root Tissue.
نویسنده
چکیده
The increment of lysine-sensitive aspartokinase (EC 2.7.2.4) activity during in vitro culture of carrot (Daucus carota, cv. Oogata sanzun) root tissue was explained in terms of derepression caused by an earlier decrease in the endogenous level of lysine, a possible end product repressor. Tissue content of free lysine decreased to about one-third of the initial level after 1 day of culture and no lysine was detected in the 2nd day. Inclusion of lysine (0.1 to 1.0 millimolar) in the culture medium resulted in a specific suppression of increase in lysine-sensitive aspartokinase activity without affecting the increase in threonine-sensitive aspartokinase activity.
منابع مشابه
Change in the proportion of two aspartokinases in carrot root tissue in response to in vitro culture.
Two isofunctional aspartokinases (EC 2.7.2.4) exist in fresh root tissue of carrot (Daucus carota, cv. Oogata sanzun). The threoninesensitive portion constitutes about 70% of the activity; the lysinesensitive, less than 20%. Culture of slices of carrot tissue for 3 days reversed the ratio as the lysine-sensitive activity preferentially increased. Inhibition by threonine and lysine was additive ...
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ورودعنوان ژورنال:
- Plant physiology
دوره 63 3 شماره
صفحات -
تاریخ انتشار 1979