This seminar presentation discusses the structure and function of coenzymes. Coenzymes are small organic molecules that bind to enzymes to help catalyze reactions. Many B vitamins act as coenzymes, facilitating the transfer of atoms between molecules during metabolism. Coenzymes bind to enzymes before other substrates and participate in redox, energy production, and transferring reactions. Deficiencies of certain coenzymes like niacin, riboflavin, pantothenic acid and vitamin B12 can cause diseases such as pellagra and megaloblastic anemia.

1. SEMINAR PRESENTATION
COENZYMES :STRUCTURE AND FUNCTION
BY:
S. DASH

2. WHAT ARE COENZYMES?????????
• Coenzymes are small molecules.
• They cannot by themselves catalyze a reaction but they can help
enzymes to do so.
• They are organic nonprotein molecules that bind with the protein
molecule (apoenzyme) to form the active enzyme (holoenzyme).

3. • Most of the B vitamins (see vitamin B complex) are coenzymes and
are essential in facilitating the transfer of atoms or groups of atoms
between molecules in the formation of carbohydrates, fats, and
proteins.
• They are regarded as coenzymes since they usually bind to the enzyme
before the other substrates are bound , since they participate in many
reactions and since they maybe reconverted to their original form by
any enzymes present within cell.

4. [1]NADH/NADPH(Nicotinamide nucleotides)

6. [2] FAD/FMN(Flavin nucleotides)
REACTION MECHANISM
FORMATION OF FORMATION OF
PRODUCT PRODUCT
WITHOUT SEMIQUINONE WITH SEMIQUINONE
AS INTERMEDIATE AS INTERMEDIATE

7. REACTION CATALYZED BY GLUCOSE OXIDASE.
MECHANISM FOLLOWED BY NADH
DEHYDROGENASE

8. [3] COENZYME-A

9. [4] ADENOSINE PHOSPHATES

10. [5] PYRIDOXAL PHOSPHATES

11. MECHANISM BY AMINO ACID RACEMASE

12. [6] THIAMINE PYROPHOSPHATE

13. REACTION CATALYSED BY PYRUVATE DECARBOXYLASE

14. [7] BIOTIN
ACETYL-CoA CARBOXYLASE
BCCP
BIOTIN CARBOXYLASE
CARBOXYLTRANSFERASE

15. [8] TETRAHYDROFOLATE(TH4)

16. REACTION CATALYSED BY SERINE TRANSHYDROXYMETHYLASE

17. [9] VITAMIN-B12

18. FUNCTIONS OF COENZYMES:
• Energy Production
• Transferring Groups
• Redox Reactions
• Antioxidants

19. BIOLOGICAL IMPORTANCE:
• Nicotinamide nucleotides : Deficiency causes pellagra.
• Flavin nucleotides : Required for proper eyesight , involved in
carbohydrate, protein and fat metabolism.
• Coenzyme A :Deficiency causes dermatitis.
• Thiamine pyrophosphate: Involved in carbohydrate metabolism

20. • Pyridoxal phosphate : Deficiency causes problems in the activity of
several hormones like G.H, Thyroid etc.
• Biotin: Deficiency causes hyperkeratosis
• Coenzyme B12: Maturation of erythroid cells

21. REFERENCES:
• Understanding enzymes by Trevor Palmer
• Advanced textbook of Food and Nutrition by Dr. M.S. Swaminathan.
• Introduction to enzyme and coenzyme chemistry by T.D.H. Bugg.