Vitamin B6: A Long Known Compound of Surprising Complexity

School of Biological Sciences, Washington State University, Pullman, WA, USA.
Molecules (Impact Factor: 2.42). 02/2009; 14(1):329-51. DOI: 10.3390/molecules14010329
Source: PubMed


In recent years vitamin B6 has become a focus of research describing the compound's critical function in cellular metabolism and stress response. For many years the sole function of vitamin B6 was considered to be that of an enzymatic cofactor. However, recently it became clear that it is also a potent antioxidant that effectively quenches reactive oxygen species and is thus of high importance for cellular well-being. In view of the recent findings, the current review takes a look back and summarizes the discovery of vitamin B6 and the elucidation of its structure and biosynthetic pathways. It provides a detailed overview on vitamin B6 both as a cofactor and a protective compound. Besides these general characteristics of the vitamin, the review also outlines the current literature on vitamin B6 derivatives and elaborates on recent findings that provide new insights into transport and catabolism of the compound and on its impact on human health.

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    • "PLP is the coenzymatically active form of vitamin B6 and plays an important role in maintaining the biochemical homeostasis of the body (Meister , 1990). There are more than 100 PLP-dependent enzymes in a cell that perform essential roles in various metabolic pathways including amino acid metabolism (such as amino acid synthesis and degradation), fatty acid metabolism (such as synthesis of polyunsaturated fatty acids) and carbohydrate metabolism (such as breakdown of glycogen) (Mooney et al., 2009). The preferred degradation route from PLP to 4-pyri- doxic acid involves the dephosphorylation of PLP by phosphatase (Jang et al., 2003) followed separately by the actions of aldehyde oxidase and b-nicotinamide adenosine dinucleotidedependent dehydrogenase (Schwartz and Kjeldgaard, 1951; Stanulovic et al., 1976). "
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    DESCRIPTION: In vitro oxidation of aldehyde oxidase from rabbit liver: Specificity toward endogenous substrates
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    • "Moreover, it has been reported that the B6 vitamer PN is implicated in the protection against the phytopathogenic fungus Cercospora nicotianae (Bilski et al., 2000). Thus, vitamin B6 is involved in a variety of vital processes in bacterial and in eukaryotic cells (Mooney et al., 2009). Only bacteria, archaea, Plasmodium, fungi and plants are capable of producing vitamin B6 de novo. "
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    ABSTRACT: Vitamin B6 is a designation for the vitamers pyridoxine, pyridoxal, pyridoxamine, and their respective 5'-phosphates. Pyridoxal 5'-phosphate, the biologically most-important vitamer, serves as a cofactor for many enzymes, mainly active in amino acid metabolism. While microorganisms and plants are capable of synthesizing vitamin B6, other organisms have to ingest it. The vitamer pyridoxine, which is used as a dietary supplement for animals and humans is commercially produced by chemical processes. The development of potentially more cost-effective and more sustainable fermentation processes for pyridoxine production is of interest for the biotech industry. We describe the generation and characterization of a Bacillus subtilis pyridoxine production strain overexpressing five genes of a non-native deoxyxylulose 5'-phosphate-dependent vitamin B6 pathway. The genes, derived from Escherichia coli and Sinorhizobium meliloti, were assembled to two expression cassettes and introduced into the B. subtilis chromosome. In vivo complementation assays revealed that the enzymes of this pathway were functionally expressed and active. The resulting strain produced 14mg/l pyridoxine in a small-scale production assay. By optimizing the growth conditions and co-feeding of 4-hydroxy-threonine and deoxyxylulose the productivity was increased to 54mg/l. Although relative protein quantification revealed bottlenecks in the heterologous pathway that remain to be eliminated, the final strain provides a promising basis to further enhance the production of pyridoxine using B. subtilis.
    Metabolic Engineering 06/2014; 25. DOI:10.1016/j.ymben.2014.06.007 · 6.77 Impact Factor
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    • "Pyridoxine produced by PGPB may have several effects on plants, but so far lack experimental evidence regarding PGPB–plant interaction. 1. Pyridoxine is a principal cofactor of amino acid, fatty acid, and carbohydrate metabolism, and its function is reported in different groups of enzymes, such as aminotransferases , aminomutases, lyases, synthases, deaminases , and phosphorylases (Mooney et al. 2009). Nitrogen, lipid, and carbohydrate metabolism, as well as effects of chlorophyll and ethylene biosynthesis, are well known to be altered by many species of PGPB (Bashan and de-Bashan 2005, 2010; Lugtenberg and Kamilova 2009). "
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    ABSTRACT: Plant growth-promoting bacteria (PGPB) can improve plant performance in many different ways, operating via a multitude of physiological, molecular, and biochemical pathways. One of the lesser known involvements in these interactions is the role of vitamins. Vitamins can be produced by plants and bacteria and also by PGPB. The main function of vitamins is to (1) act as a cofactor in diverse metabolic pathways, (2) facilitate production of essential compounds for plants and bacteria, (3) induce resistance against pathogens, (4) directly promote plant growth, and (5) participate in energy conversion in the plant from stored compounds. Most of the roles of specific vitamins in PGPB–plant interactions are still little known or completely unknown. This overview presents what is known about vitamins detected in potential PGPB, presents proposals for the potential role of vitamins in PGPB–plant interactions based on the known function of these vitamins in plants and bacteria, and proposes research avenues in this topic that are worth exploring.
    Biology and Fertility of Soils 01/2014; 50(3). DOI:10.1007/s00374-013-0894-3 · 3.40 Impact Factor
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