Niacin vitamin fatty acid metabolism

Several of the B vitamins are essential for normal fatty-acid metabolism (Table 2). Pantothenic acid is a constituent of CoA and is thus required for numerous reactions of fatty acids. Niacin and riboflavin are necessary for the synthesis of oxidized and reduced NAD(P) and FAD, respectively. These compounds play essential roles in fatty-acid oxidation, synthesis, and elongation. Biotin is a constituent of acetyl-CoA carboxylase and pyruvate carboxylase, both of which are involved in the synthesis of fatty acids from glucose. Thiamine is required for activity of the pyruvate dehydrogenase complex, which also participates in fatty-acid synthesis from glucose. 

Niacin is a water-soluble vitamin. The RDA of niacin for the adult man is 19 mg. Niacin is converted in the bi>dy to the cofactor nicotinamide adenine dinucleotide (NAD). NAD also exists in a phosphorylated form, NADP The phosphate group occurs on the 2-hydrr>xyl group of the AMP half of the coenzyme, NAD and NADP are used in the catalysis of oxidation and reduction reactions. These reactions are called redox reactions. NAD cycles between the oxidized form, NAD, and the reduced form, NADH + H. The coenzyme functions to accept and donate electrons. NADP behaves in a similar fashion. It occurs as NADP and NADPH + HT The utilization of NAD is illustrated in the sections on glycolysis, the malatc-aspartate shuttle, ketone body metabolism, and fatty acid oxidation. The utilization of NADP is illustrated in the sectirrns concerning fatty acid synthesis and the pentose phosphate pathway. 

Animals also depend on plants for essential organic molecules that they are unable to make. We call some of these molecules vitamins. Several vitamins, including niacin, riboflavin, pyridoxine, and biotin, are key players in catabolic and anabolic metabolism, and deficiencies in these vitamins have severe effects. Also, animals are incapable of synthesizing polyunsaturated fatty acids (fatty acids with more than one double bond). Polyunsaturated fatty acids are essential components of membrane lipids and must be obtained in the diet. So, the next time you have a salad, pay a tribute to photosynthesis. 

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