sirtuin


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sirtuin

(sûr′to͞o-ĭn, -tyo͞o-)
n.
Any of a family of enzymes that occur in all living organisms and are thought to regulate cellular aging, apoptosis, and resistance to stress in more complex eukaryotic organisms.
Any of a class of proteins that possess either histone deacetylase—more commonly—or mono-ribosyltransferase activity, named after Sir2, the cell-regulating yeast gene silent mating-type information regulation 2. Sirtuins regulate critical biological pathways in eubacteria, archaea and eukaryotes.
Sirtuins influence ageing, transcription, apoptosis, stress resistance, and affect energy efficiency and alertness during hypoglycaemia
Most sirtuins are protein deacetylases in which sirtuin-mediated deacetylation couples lysine deacetylation to NAD hydrolysis—instead of simple hydrolysis of acetyl-lysine residues—yielding O-acetyl-ADP-ribose, the deacetylated substrate and nicotinamide. The dependence of sirtuins on NAD links their enzymatic activity directly to the energy status of the cell via the cellular NAD:NADH ratio, the absolute levels of NAD, NADH or nicotinamide or a combination of these variables.

sirtuin

(sĭr′too-ĭn)
Any of a class of proteins that are coded by the SIR family of genes. These proteins contribute to chromosome repair and may have a role in extending the life span of cells.
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In 2003, we introduced resveratrol based on its ability to activate sirtuin longevity factors.
Sirtuin inhibition attenuates the production of inflammatory cytokines in lipopolysaccharide-stimulated macrophages.
However, despite investing millions of dollars to develop a drug that activates Sirtuin genes, several global pharma majors, including GlaxoSmithKline Pharmaceuticals, which had acquired Sinclair's Sirtris Pharma-ceuticals in 2004, and Pfizer, failed to come up with a marketable drug and, subsequently, the projects were shelved.
Sirtfoods, foods that will affect sirtuin genes, are the latest fad in nutrition science.
The final nuclear sirtuin, SIRT7, has been less well characterized but localizes to the nucleolus and regulates rDNA transcription [122].
In Sirtuin family, SIRT1 can fine-tune cellular response to hypoxia by deacetylating HIF-1a.
Her current work contributes to the understanding of how mitochondrial sirtuins regulate tumor cell metabolism.
Sirtuin 1, or SIRT1, is known to play an important role in maintaining metabolic balance in multiple tissues, and studies in various organisms have shown that activating the protein can lead to many health benefits.
Protein Sirtuin have long been connected to lifespan extension and calorie restriction.
Experiments on cultivated mouse cells in the laboratory confirmed that metformin has a direct effect on the vascular function through interaction with a protein called sirtuin 1, which is encoded by the SIRT1 gene, known to play a role in ageing.
Detractors had claimed Sinclair's data were influenced by a fluorescent chemical--one that doesn't occur in nature--that he used to measure the activation of sirtuin proteins by resveratrol-like compounds.