Pantothenic Acid A growth factor occurring in all types of animal and plant tissue was first designated vitamin B3 and later named pantothenic acid (from Greek for “everywhere”). Dietary sources include liver and other organ meats, milk, eggs, peanuts, legumes, mushrooms, salmon, and whole grains. Approximately 50% of pantothenate in food is available for absorption. Pantothenate is metabolically converted to 4-phosphopantetheine, which becomes covalently bound to either serum acyl carrier protein or coenzyme A. Coenzyme A is a highly important acyl-group transfer coenzyme involved in many reactions of many reaction types. The RDA for pantothenic acid in adults is 5 mg/day. Whole blood pantothenate of less than 100 g/dL and urinary excretion of less than 1 mg/day are regarded as indicative of deficiency. Reference range for urine is 1–15 mg/day or 5–68 mol/day. Assays using a load test look for excretion of the acetylated p-aminobenzoic acid that is formed.