NAD+ is essential for life in all organisms, both as a coenzyme for oxidoreductases and as a source of ADPribosyl groups used in various reactions, including those that retard aging in experimental systems. Nicotinic acid and nicotinamide were defined as the vitamin precursors of NAD+ in Elvehjem's classic discoveries of the 1930s. The accepted view of eukaryotic NAD+ biosynthesis, that all anabolism flows through nicotinic acid mononucleotide, was challenged experimentally and revealed that nicotinamide riboside is an unanticipated NAD+ precursor in yeast. Nicotinamide riboside kinases from yeast and humans essential for this pathway were identified and found to be highly specific for phosphorylation of nicotinamide riboside and the cancer drug tiazofurin. Nicotinamide riboside was discovered as a nutrient in milk, suggesting that nicotinamide riboside is a useful compound for elevation of NAD+ levels in humans.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/s0092-8674(04)00416-7 | DOI Listing |
Cell Mol Biol Lett
January 2025
Enzymology and Metabolism Group, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4367, Belvaux, Luxembourg.
Background: Metabolism is error prone. For instance, the reduced forms of the central metabolic cofactors nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH), can be converted into redox-inactive products, NADHX and NADPHX, through enzymatically catalyzed or spontaneous hydration. The metabolite repair enzymes NAXD and NAXE convert these damaged compounds back to the functional NAD(P)H cofactors.
View Article and Find Full Text PDFJ Neurochem
January 2025
The Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA.
Alzheimer disease is a neurodegenerative pathology-modifying mitochondrial metabolism with energy impairments where the effects of biological sex and DNA repair deficiencies are unclear. We investigated the therapeutic potential of dietary ketosis alone or with supplemental nicotinamide riboside (NR) on hippocampal intermediary metabolism and mitochondrial bioenergetics in older male and female wild-type (Wt) and 3xTgAD-DNA polymerase-β-deficient (3xTg/POLβ) (AD) mice. DNA polymerase-β is a key enzyme in DNA base excision repair (BER) of oxidative damage that may also contribute to mitochondrial DNA repair.
View Article and Find Full Text PDFCell Mol Life Sci
December 2024
Center for Mitochondrial Research and Medicine, College of Medicine Chang Gung University, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
Imbalances in gut microbiota and their metabolites have been implicated in osteoporotic disorders. Trimethylamine-n-oxide (TMAO), a metabolite of L-carnitine produced by gut microorganisms and flavin-containing monooxygenase-3, is known to accelerate tissue metabolism and remodeling; however, its role in bone loss remained unexplored. This study investigates the relationship between gut microbiota dysbiosis, TMAO production, and osteoporosis development.
View Article and Find Full Text PDFSubcell Biochem
December 2024
Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, Lørenskog, Norway.
Nicotinamide adenine dinucleotide (oxidized form, NAD) serves as a co-substrate and co-enzyme in cells to execute its key roles in cell signalling pathways and energetic metabolism, arbitrating cell survival and death. It was discovered in 1906 by Arthur Harden and William John Young in yeast extract which could accelerate alcohol fermentation. NAD acts as an electron acceptor and cofactor throughout the processes of glycolysis, Tricarboxylic Acid Cycle (TCA), β oxidation, and oxidative phosphorylation (OXPHOS).
View Article and Find Full Text PDFPurpose: The aim of this study was to test whether oral administration of nicotinamide riboside (NR), the nicotinamide adenine dinucleotide (NAD+) precursors, protect retina ganglion cells (RGCs) from neurodegeneration in DBA/2J (D2) mice, which is a widely used mouse model of age-related inherited glaucoma.
Method: Oral NR or NAM administration (NR low dose: 1150mg/kg; NR high dose: 4200mg/kg; NAM low dose group: 500mg/kg; NAM high dose: 2000mg/kg of body weight per day) essentially started when D2 mice were 4 or 9 months old and continued up to 12 months old. Control cohort identically received food/water without NAM or NR.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!