PLP and PMP Radicals: A New Paradigm in Coenzyme B6 Chemistry

Agnihotri, Gautam; Liu, Hung‐wen

doi:10.1006/bioo.2001.1211

Cited by 15 publications

(8 citation statements)

References 76 publications

(56 reference statements)

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“…PMP serves as a cofactor for only a few enzymes (Agnihotri and Liu, 2001;Adrover et al, 2009). And no evidence indicates that the enzymes involved in starch biosynthesis are PMP dependent (http://bioinformatics.…”

Section: Vitamin B 6 Biosynthesis Is Essential To Embryogenesis But Lmentioning

confidence: 99%

Small kernel2 Encodes a Glutaminase in Vitamin B₆ Biosynthesis Essential for Maize Seed Development

et al. 2017

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Vitamin B, an essential cofactor for a range of biochemical reactions and a potent antioxidant, plays important roles in plant growth, development, and stress tolerance. Vitamin B deficiency causes embryo lethality in Arabidopsis (), but the specific role of vitamin B biosynthesis in endosperm development has not been fully addressed, especially in monocot crops, where endosperm constitutes the major portion of the grain. Through molecular characterization of a () mutant in maize, we reveal that vitamin B has differential effects on embryogenesis and endosperm development in maize. The B vitamer pyridoxal 5'-phosphate (PLP) is drastically reduced in both the embryo and the endosperm. However, whereas embryogenesis of the mutant is arrested at the transition stage, endosperm formation is nearly normal. Cloning reveals that encodes the glutaminase subunit of the PLP synthase complex involved in vitamin B biosynthesis de novo. partially complements the Arabidopsis vitamin B-deficient mutant and pyridoxine auxotrophic mutant MML21. is constitutively expressed in the maize plant, including developing embryos. Analysis of B vitamers indicates that the endosperm accumulates a large amount of pyridoxamine 5'-phosphate (PMP). These results indicate that vitamin B is essential to embryogenesis but has a reduced role in endosperm development in maize. The vitamin B required for seed development is synthesized in the seed, and the endosperm accumulates PMP probably as a storage form of vitamin B.

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Section: Vitamin B 6 Biosynthesis Is Essential To Embryogenesis But Lmentioning

confidence: 99%

Small kernel2 Encodes a Glutaminase in Vitamin B₆ Biosynthesis Essential for Maize Seed Development

et al. 2017

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“…Its topology corresponds to those of the other enzymes from subgroup II of the -family of vitamin B 6 enzymes (Mehta & Christen, 1994;Schulze et al, 2006). Almost all B 6 cofactors, including PLP and PMP, depend on the pyridinium moiety to stabilize high-energy anionic intermediates during reaction (Agnihotri & Liu, 2001). GSAM catalyzes the transamination of GSA substrate to ALA product by an unusual intramolecular exchange of amino and oxo groups via the intermediate 4,5-diaminovalerate (DAVA).…”

Section: Introductionmentioning

confidence: 99%

Crystal structure of glutamate-1-semialdehyde-2,1-aminomutase fromArabidopsis thaliana

Song

Jiang

et al. 2016

Acta Cryst Sect F

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“…Most reactions catalyzed by vitamin B 6 –containing enzymes are not generally considered to involve radical intermediates. The mechanism of almost all such enzymes is thought to be based on their ability to stabilize high-energy anionic intermediates in their reaction pathways by the pyridinium moiety of PLP/PMP (64). However, a few exceptions are known.…”

Section: Mechanisms Contributing To the Oxidation Reactions Catalmentioning

confidence: 99%

A Survey of Oxidative Paracatalytic Reactions Catalyzed by Enzymes that Generate Carbanionic Intermediates: Implications for ROS Production, Cancer Etiology, and Neurodegenerative Diseases

Bunik

Schloss

Pinto

et al. 2011

Advances in Enzymology - And Related Areas of Molecular Biology

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PLP and PMP Radicals: A New Paradigm in Coenzyme B6 Chemistry

Cited by 15 publications

References 76 publications

Small kernel2 Encodes a Glutaminase in Vitamin B₆ Biosynthesis Essential for Maize Seed Development

Small kernel2 Encodes a Glutaminase in Vitamin B₆ Biosynthesis Essential for Maize Seed Development

Crystal structure of glutamate-1-semialdehyde-2,1-aminomutase fromArabidopsis thaliana

A Survey of Oxidative Paracatalytic Reactions Catalyzed by Enzymes that Generate Carbanionic Intermediates: Implications for ROS Production, Cancer Etiology, and Neurodegenerative Diseases

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PLP and PMP Radicals: A New Paradigm in Coenzyme B6 Chemistry

Cited by 15 publications

References 76 publications

Small kernel2 Encodes a Glutaminase in Vitamin B6 Biosynthesis Essential for Maize Seed Development

Small kernel2 Encodes a Glutaminase in Vitamin B6 Biosynthesis Essential for Maize Seed Development

Crystal structure of glutamate-1-semialdehyde-2,1-aminomutase fromArabidopsis thaliana

A Survey of Oxidative Paracatalytic Reactions Catalyzed by Enzymes that Generate Carbanionic Intermediates: Implications for ROS Production, Cancer Etiology, and Neurodegenerative Diseases

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Small kernel2 Encodes a Glutaminase in Vitamin B₆ Biosynthesis Essential for Maize Seed Development

Small kernel2 Encodes a Glutaminase in Vitamin B₆ Biosynthesis Essential for Maize Seed Development