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Zhu JP, Gong H, Labreche F, Kou XH, Wu CE, Fan GJ, Li TT, Wang JH, Shen DB. Age-dependent alteration in metabolism of vitamin B 6 , neurotransmitters, and amino acids after 4'-O-methylpyridoxine administration in rats. J Food Sci 2021; 87:466-480. [PMID: 34914095 DOI: 10.1111/1750-3841.15997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/26/2021] [Accepted: 11/01/2021] [Indexed: 11/27/2022]
Abstract
4'-O-methylpyridoxine (MPN), a recognized antivitamin B6 compound, is a potentially poisonous substance found in Ginkgo biloba L. In this work, the effects of MPN on the metabolism of vitamin B6 , neurotransmitters, and amino acids were compared in the plasma and brain of young and adult rats under various administration times. Results showed that the contents of MPN residues in the plasma and brain of young rats were 12.72 and 14.76 µM higher than adult rats, respectively. Moreover, the levels of 5-hydroxytryptamine and dopamine in the brain of young rats have decreased by 13.78% and 7.19%, respectively, compared with the control group, at 2 h after MPN administration. Furthermore, the principal component analysis revealed that MPN was an important contributor to the amino acid composition in the brain of young rats. These results suggest that age may lead to different toxic effects of MPN. PRACTICAL APPLICATION: 4'-O-methylpyridoxine is primarily responsible for poisoning due to overconsumption of Ginkgo biloba seeds. This study will provide an exploratory understanding of the age-dependent toxicity of 4'-O-methylpyridoxine.
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Affiliation(s)
- Jin-Peng Zhu
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, China
| | - Hao Gong
- College of Food Engineering, Xuzhou University of Technology, Xuzhou, China
| | - Faiza Labreche
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, China
| | - Xiao-Hong Kou
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Cai-E Wu
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, China.,Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, China
| | - Gong-Jian Fan
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, China.,Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, China
| | - Ting-Ting Li
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, China.,Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, China
| | - Jia-Hong Wang
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, China.,Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, China
| | - Dong-Bei Shen
- College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, China
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Han H, Xu B, Zeng W, Zhou J. Regulating the biosynthesis of pyridoxal 5'-phosphate with riboswitch to enhance L-DOPA production by Escherichia coli whole-cell biotransformation. J Biotechnol 2020; 321:68-77. [DOI: 10.1016/j.jbiotec.2020.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023]
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Silverman RB. Design and Mechanism of GABA Aminotransferase Inactivators. Treatments for Epilepsies and Addictions. Chem Rev 2018; 118:4037-4070. [PMID: 29569907 DOI: 10.1021/acs.chemrev.8b00009] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
When the brain concentration of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) diminishes below a threshold level, the excess neuronal excitation can lead to convulsions. This imbalance in neurotransmission can be corrected by inhibition of the enzyme γ-aminobutyric acid aminotransferase (GABA-AT), which catalyzes the conversion of GABA to the excitatory neurotransmitter l-glutamic acid. It also has been found that raising GABA levels can antagonize the rapid elevation and release of dopamine in the nucleus accumbens, which is responsible for the reward response in addiction. Therefore, the design of new inhibitors of GABA-AT, which increases brain GABA levels, is an important approach to new treatments for epilepsy and addiction. This review summarizes findings over the last 40 or so years of mechanism-based inactivators (unreactive compounds that require the target enzyme to catalyze their conversion to the inactivating species, which inactivate the enzyme prior to their release) of GABA-AT with emphasis on their catalytic mechanisms of inactivation, presented according to organic chemical mechanism, with minimal pharmacology, except where important for activity in epilepsy and addiction. Patents, abstracts, and conference proceedings are not covered in this review. The inactivation mechanisms described here can be applied to the inactivations of a wide variety of unrelated enzymes.
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Affiliation(s)
- Richard B Silverman
- Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3113 , United States
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Milano T, Gulzar A, Narzi D, Guidoni L, Pascarella S. Molecular dynamics simulation unveils the conformational flexibility of the interdomain linker in the bacterial transcriptional regulator GabR from Bacillus subtilis bound to pyridoxal 5'-phosphate. PLoS One 2017; 12:e0189270. [PMID: 29253008 PMCID: PMC5734734 DOI: 10.1371/journal.pone.0189270] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 11/22/2017] [Indexed: 11/18/2022] Open
Abstract
GabR from Bacillus subtilis is a transcriptional regulator belonging to the MocR subfamily of the GntR regulators. The structure of the MocR regulators is characterized by the presence of two domains: i) a N-terminal domain, about 60 residue long, possessing the winged-Helix-Turn-Helix (wHTH) architecture with DNA recognition and binding capability; ii) a C-terminal domain (about 350 residue) folded as the pyridoxal 5'-phosphate (PLP) dependent aspartate aminotransferase (AAT) with dimerization and effector binding functions. The two domains are linked to each other by a peptide bridge. Although structural and functional characterization of MocRs is proceeding at a fast pace, virtually nothing is know about the molecular changes induced by the effector binding and on how these modifications influence the properties of the regulator. An extensive molecular dynamics simulation on the crystallographic structure of the homodimeric B. subtilis GabR has been undertaken with the aim to envisage the role and the importance of conformational flexibility in the action of GabR. Molecular dynamics has been calculated for the apo (without PLP) and holo (with PLP bound) forms of the GabR. A comparison between the molecular dynamics trajectories calculated for the two GabR forms suggested that one of the wHTH domain detaches from the AAT-like domain in the GabR PLP-bound form. The most evident conformational change in the holo PLP-bound form is represented by the rotation and the subsequent detachment from the subunit surface of one of the wHTH domains. The movement is mediated by a rearrangement of the linker connecting the AAT domain possibly triggered by the presence of the negative charge of the PLP cofactor. This is the second most significant conformational modification. The C-terminal section of the linker docks into the "active site" pocket and establish stabilizing contacts consisting of hydrogen-bonds, salt-bridges and hydrophobic interactions.
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Affiliation(s)
- Teresa Milano
- Dipartimento di Scienze biochimiche “A. Rossi Fanelli”, Sapienza Università di Roma, Italy
| | - Adnan Gulzar
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, L’Aquila, Italy
| | - Daniele Narzi
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, L’Aquila, Italy
| | - Leonardo Guidoni
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, L’Aquila, Italy
| | - Stefano Pascarella
- Dipartimento di Scienze biochimiche “A. Rossi Fanelli”, Sapienza Università di Roma, Italy
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