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Trigonelline is an alkaloid with chemical formula C 7 H 7 N O 2.It is a zwitterion formed by the methylation of the nitrogen atom of niacin (vitamin B 3).Trigonelline is a product of niacin metabolism that is excreted in the urine of mammals.
The three vitamin precursors used in these salvage metabolic pathways are nicotinic acid (NA), nicotinamide (Nam) and nicotinamide riboside (NR). [6] These compounds can be taken up from the diet and are termed vitamin B 3 or niacin. However, these compounds are also produced within cells and by digestion of cellular NAD +.
The words protein, polypeptide, and peptide are a little ambiguous and can overlap in meaning. Protein is generally used to refer to the complete biological molecule in a stable conformation, whereas peptide is generally reserved for a short amino acid oligomers often lacking a stable 3D structure. But the boundary between the two is not well ...
The Danish-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the coagulation of blood following wounding (from the Danish word Koagulation). At the time, most (but not all) of the letters from F through to J were already designated, so the use of the ...
Vitamin A status involves eye health via two separate functions. Retinal is an essential factor in rod cells and cone cells in the retina responding to light exposure by sending nerve signals to the brain. An early sign of vitamin A deficiency is night blindness. [6] Vitamin A in the form of retinoic acid is essential to normal epithelial cell ...
In oxyhemoglobin the iron atom is located in the plane of the porphyrin ring, but in the paramagnetic deoxyhemoglobin the iron atom lies above the plane of the ring. [11] This change in spin state is a cooperative effect due to the higher crystal field splitting and smaller ionic radius of Fe 2+ in the oxyhemoglobin moiety.
Alanine is an aliphatic amino acid, because the side-chain connected to the α-carbon atom is a methyl group (-CH 3). Alanine is the simplest α-amino acid after glycine . The methyl side-chain of alanine is non-reactive and is therefore hardly ever directly involved in protein function. [ 12 ]
Vitamin E is a group of eight compounds related in molecular structure that includes four tocopherols and four tocotrienols. The tocopherols function as fat-soluble antioxidants which may help protect cell membranes from reactive oxygen species. Vitamin E is classified as an essential nutrient for humans.