Useful for basic Biochemistry students

1. Role of cofactors in Metabolism
Sunil Saundankar
Satana College, Satana.

2. • Vitamins
• Vitamins are organic molecules needed for variety of
biological function within the body.
• The most important function of the vitamins is to
serve as cofactors (co-enzymes) for enzymatic
reactions.
• protein + coenzyme (vitamin)= enzyme
• protein + cofactor (metal ion)= enzyme
• the vitamins cannot be synthesized by mammalian
cells and, therefore, must be supplied in the diet in
small quantities (microgram or milligram per day).

3. Coenzyme and vitamins
• • Most of the B vitamins 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
• coenzymes: complex organic molecules that work with enzymes to
facilitate the enzymes’ activity. Many coenzymes have B vitamins as
part of their structures.
• coenzymes is to act as transporters of chemical groups from one
reactant to another.
• Examples include;
• - nicotinamide adenine dinucleotide (NAD), which accepts
hydrogen (and gives it up in another reaction),
• -ATP, which gives up phosphate groups while transferring chemical
energy

4. • Vitamin (water soluble vitamin, fat soluble vitamin): an organic
substance needed in small amounts for normal body functions that
the body cannot synthesize in adequate amounts
• enzyme: a protein that is a catalyst
• cofactor: a small, inorganic or organic substance that facilitates
enzyme action; includes both organic coenzymes made from
vitamins and inorganic substances such as minerals
• Coenzymes are non-protein organic molecules that are mostly
derivatives of vitamins soluble in water by phosphorylation; they
bind apoenzyme to proteins to produce an active holoenzyme
• prosthetic group: a cofactor permanently associated with the
protein, often covalently bound
• holoenzyme: catalytically active enzyme-cofactor complex.
• apoenzyme: an enzyme without its cofactor enzymatically
inactive protein

5. • The vitamins are of two distinct types, water
soluble and fat soluble.
• Water soluble vitamins• -soluble in water,
consist of carbon, hydrogen, oxygen nitrogen,
sulfur, cobalt,
• -deficiency usually occur more than fat
soluble vitamins
• -Water-soluble vitamins that body cannot
store

6. Thiamine or vitamin B1
• thiamine-sulfur containing water soluble vitamin of B complex,
exist in tissues in the active form of Thiamine Pyrophosphate (TPP)
• - Thiamine Pyrophosphate (TPP) is essential co-enzyme involve in
energy extraction and cellular process in catabolism of sugar and
amino acid
• -human and other animal obtain it through diet
• Thiamin chemical structure Thiamin is derived from a substituted
aminopyrimidine ring and a thiazole ring with methyl and
hydroxyethyl side chains linked by a methylene bridge. C12
H17N4OS
• Thiamin pyrophosphate the active form of vitaminB1. A thiazole
ring is found naturally in thiamin Thiazole is a heterocyclic
compound featuring both a nitrogen atom and sulfur atom as part
of the aromatic five-membered ring. a thiazole ring stabilizes charge
and electron transfer