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J Biol Chem. 2014 Mar 21;289(12):8203-16. doi: 10.1074/jbc.M113.540526. Epub 2014 Feb 6.

The pseudoenzyme PDX1.2 boosts vitamin B6 biosynthesis under heat and oxidative stress in Arabidopsis.

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From the Department of Botany and Plant Biology, University of Geneva, 1211 Geneva, Switzerland and.


Vitamin B6 is an indispensable compound for survival, well known as a cofactor for numerous central metabolic enzymes and more recently for playing a role in several stress responses, particularly in association with oxidative stress. Regulatory aspects for the use of the vitamin in these roles are not known. Here we show that certain plants carry a pseudoenzyme (PDX1.2), which is involved in regulating vitamin B6 biosynthesis de novo under stress conditions. Specifically, we demonstrate that Arabidopsis PDX1.2 enhances the activity of its catalytic paralogs by forming a heterododecameric complex. PDX1.2 is strongly induced by heat as well as singlet oxygen stress, concomitant with an enhancement of vitamin B6 production. Analysis of pdx1.2 knockdown lines demonstrates that boosting vitamin B6 content is dependent on PDX1.2, revealing that this pseudoenzyme acts as a positive regulator of vitamin B6 biosynthesis during such stress conditions in plants.


Antioxidants; Biosynthesis; Enzyme Catalysis; Plant Biochemistry; Pyridoxal Phosphate; Stress Response

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