Vitamin b2

Introduction about Vitamin B2, Chemistry of Riboflavin, Biochemical Functions of Riboflavin, Recommended Dietary Allowance of Vitamin B2, Dietary Sources of Riboflavin, Deficiency Symptoms of Vitamin B2, Synthesis of FMN, FAD from Riboflavin pathway, Coenzymes of Riboflavin.

1. Chemistry and Biochemical role, RDA and Deficiency diseases of Vitamin B2 Jasmine Juliet .R Biotechnology Department Agricultural college and Research & Institute Madurai.

2. Riboflavin (Vitamin B2) Riboflavin which has also known as Vitamin B2, Vitamin G and “ the yellow enzyme” was recognized as a vitamin in 1917. As early as 1897, a London chemist had observed in milk whey a water-soluble pigment with peculiar yellow-green fluorescence. It was given the chemical group name flavin from the Latin word for Yellow. Later because the vitamin was found also to contain a sugar named ribose , the name riboflavin was adopted .

3. Riboflavin (Vitamin B2 ) - Chemistry Riboflavin through its coenzymes takes part in a variety of cellular oxidation-reduction reactions. Riboflavin contains 6,7-dimethyl isoalloxazine ( a hetrocyclic 3 ring structure) attached to D- ribitol by a nitrogen atom.

4. Riboflavin (Vitamin B2) - Chemistry

5. Riboflavin (Vitamin B2) - Chemistry Coenzymes of Riboflavin Flavin mononucleotide (FMN) and Flavin Adenine dinucleotide (FAD) are the two coenzyme forms of riboflavin. The ribitol (5 carbon) is linked to a phosphate in FMN. FAD is formed from FMN by the transfer of an AMP moiety from ATP.

6. Riboflavin (Vitamin B2) - Biochemical functions I. The flavin coenzymes (mostly FAD and to a lesser extent FMN) participate in many redox reactions responsible for energy production. The functional unit of both the coenzymes is isoalloxazine ring which serves as an acceptor of two hydrogen atoms (with electrons). FMN or FAD undergo identical reversible reactions accepting two hydrogen atoms forming FMNH2 or FADH2.

7. Riboflavin (Vitamin B2) – Biochemical Functions II. Enzymes that use flavin coenzymes (FMN or FAD) are called flavoproteins . Many flavoproteins contain metal atoms (iron, molybdenum etc.) which are known as metalloflavoproteins . The coenzymes, FAD and FMN are associated with several enzymes involved in carbohydrate, lipid, protein, and purine metabolisms , besides the electron transport chain.

8. Riboflavin (Vitamin B2) - Recommended dietary allowance (RDA) The daily requirement of riboflavin for an adult is 1.2-1.7mg . Higher intakes (by 0.2-0.5 mg/day) are advised for pregnant and lactating women.

9. Riboflavin (Vitamin B2) – Dietary Sources Milk and milk products, meat, eggs, liver, kidney, are rich sources . Cereals , fruits, Vegetables and fish are moderate sources.

10. Riboflavin (Vitamin B2) - Deficiency Symptoms Riboflavin deficiency symptoms include: C heilosis (fissure at the corner of the mouth ), G lossitis (tongue smooth and purplish) and D ermatitis . Assay of the enzyme Glutathione R eductase in erythrocytes will be useful in assessing the riboflavin deficiency.