Vitamins and Minerals PANTOTHENIC ACID AND RIBOFLAVIN September 24, 2014

Pantothenic acid (from diet) Coenzyme A ADP attaches here A thiol group (from Cysteine) is added here

Coenzyme A HMG-CoA Fatty acid synthesis Malonyl-coA Succinyl-CoA Citrate TCA! 95% of ATP! PANTOTHENIC ACID Cholesterol synthesis Heme synthesis Acetyl-CoA

Heme synthesis starts with succinyl coA and glycine. ( PLP)

SYNTHESIS OF ACETYL-CoA FROM PYRUVATE TRANSFER OF ACETYL GROUP TO OXALOACETATE, TO MAKE CITRATE (FIRST STEP IN THE TCA)

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

DIETARY RIBOFLAVIN IS ALSO MODIFIED WITH A NUCLEIC ACID, TO MAKE THE ACTIVE FORMS. How many vitamins require this kind of modification? RIBOFLAVIN

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.

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

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?

C CH 3 NADH+H+ NAD+ METHYLENE TETRAHYDROFOLATE METHY TETRAHYDROFOLATE Riboflavin participates in this key step in the generation of active folate

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.

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 POUNDS OF FLOUR. This might contain 0.6 mg of riboflavin, which is 50% of the RDA.

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.