Lysine catabolism, an effective versatile regulator of lysine level in plants
In: Amino Acids, Jg. 30 (2006-03-01), S. 121-125
Online
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Zugriff:
Lysine is a nutritionally important essential amino acid, whose synthesis in plants is strongly regulated by the rate of its synthesis. Yet, lysine level in plants is also finely controlled by a super-regulated catabolic pathway that catabolizes lysine into glutamate and acetyl Co-A. The first two enzymes of lysine catabolism are synthesized from a single LKR/SDH gene. Expression of this gene is subject to compound developmental, hormonal and stress-associated regulation. Moreover, the LKR/SDH gene of different plant species encodes up to three distinct polypeptides: (i) a bifunctional enzyme containing the linked lysine-ketoglutarate (LKR) and saccharopine dehydrogenase (SDH) whose LKR activity is regulated by its linked SDH enzyme; (ii) a monofunctional SDH encoded by an internal promoter, which is a part of the coding DNA region of the LKR/SDH gene; and (iii) a monofunctional, highly potent LKR that is formed by polyadenylation within an intron. LKR activity in the bifunctional LKR/SDH polypeptide is also post-translationally regulated by phosphorylation by casein kinase-2 (CK2), but the consequence of this regulation is still unknown. Why is lysine metabolism super-regulated by synthesis and catabolism? A hypothesis addressing this important question is presented, suggesting that lysine may serve as a regulator of plant growth and interaction with the environment.
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Lysine catabolism, an effective versatile regulator of lysine level in plants
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Autor/in / Beteiligte Person: | Less, Hadar ; Stepansky, Asya ; Zhu, Xiaohong ; Galili, Gad ; Angelovici, Ruthie ; Aharon, R. |
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Zeitschrift: | Amino Acids, Jg. 30 (2006-03-01), S. 121-125 |
Veröffentlichung: | Springer Science and Business Media LLC, 2006 |
Medientyp: | unknown |
ISSN: | 1438-2199 (print) ; 0939-4451 (print) |
DOI: | 10.1007/s00726-005-0246-1 |
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