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Vitamins and Minerals PANTOTHENIC ACID AND RIBOFLAVIN September 24, 2014
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Pantothenic acid (from diet) Coenzyme A ADP attaches here A thiol group (from Cysteine) is added here
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Coenzyme A HMG-CoA Fatty acid synthesis Malonyl-coA Succinyl-CoA Citrate TCA! 95% of ATP! PANTOTHENIC ACID Cholesterol synthesis Heme synthesis Acetyl-CoA
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Heme synthesis starts with succinyl coA and glycine. ( PLP)
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SYNTHESIS OF ACETYL-CoA FROM PYRUVATE TRANSFER OF ACETYL GROUP TO OXALOACETATE, TO MAKE CITRATE (FIRST STEP IN THE TCA)
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Plasma concentration is about mg/L, and it’s easily filtered into the glomerular filtrate, and not completely resorbed into the proximal tubule. Trace losses of some of the B-vitamins in the urine are a common event Since about 200 liters of GF are formed every day, about 200 mg of pantothenic acid leaves the bloodstream into the filtrate. Urinary losses of 2-7 mg/day result, so we need this in our diet. The RDA of 5 mg/day compensates for these losses. The USDA does NOT recommend fortification. Deficiency is very uncommon. Linus Pauling Institute website: good core resource http://lpi.oregonstate.edu/infocenter/vitamins/pa/
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DIETARY RIBOFLAVIN IS ALSO MODIFIED WITH A NUCLEIC ACID, TO MAKE THE ACTIVE FORMS. How many vitamins require this kind of modification? RIBOFLAVIN
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This reduction to FADH 2 adds two high-energy electrons to the flavin group, which then donates those electrons to the ETC. OCCURS IN THE TCA.
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FADH 2 is a riboflavin-dependent component. The FADH 2 produced also contributes electrons for ATP synthesis by the E.T.C. Also has a role here
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Riboflavin: role of beta-oxidation of fatty acids Beta-oxidation of fatty acids provides about 40% of the energy in the typical American diet. Riboflavin is essential for this pathway. FATTY ACID TCA How many vitamins needed, to make Acetyl-CoA from a fatty acid?
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C CH 3 NADH+H+ NAD+ METHYLENE TETRAHYDROFOLATE METHY TETRAHYDROFOLATE Riboflavin participates in this key step in the generation of active folate
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Riboflavin is needed to convert oxidized glutathione to reduced glutathione, as part of the enzyme glutathione reductase (GSH-Red). Levels of GSH-Red in RBC lead to a simple measurement of riboflavin status, as will be discussed in lecture. Similar to niacin, riboflavin is part of many biochemical pathways. This summary just covers a few of its many functions.
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What is “Enriched” flour? According to the FDA, enriched flour must have the following quantities of nutrients per pound, to qualify:FDA -2.9 milligrams of thiaminthiamin -1.8 milligrams of riboflavinriboflavin -24 milligrams of niacinniacin -0.7 milligrams of folic acid,folic acid -20 milligrams of iron.iron -Calcium also may be added at a minimum of 960 milligrams per pound.Calcium A TYPICAL BAKERY LOAF (1 pound) WILL CONTAIN ABOUT 0.25-0.5 POUNDS OF FLOUR. This might contain 0.6 mg of riboflavin, which is 50% of the RDA.
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Is there RIBOFLAVIN deficiency in the US? It’s a common feature in alcoholics, but those individuals often have MULTIPLE micronutrient deficiencies. In general, the practice of adding riboflavin to our diet has protected MOST people from deficiency; but the cases where supplements are needed deserve careful attention. Thyroid disease, diabetes, and use of some antidepressants may put people at risk; for those people, it’s important to use a multivitamin to make sure that deficiency does not occur. A number of illnesses appear to increase micronutrient deficiency; a good argument (which could be debated) could be made that all people with a clinical disorder of any kind should receive a multi-vitamin supplement.
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