Coenzymes, vitamin derived coenzymes and their functions.

1. COENZYMES
(TPP, CoA, FMN)
BY- SARAH HAMID
M.Sc BIOTECHNOLOGY
PGY-1

2. IMPORTANT TERMS
• Catalyze- To cause or accelerate a reaction.
• Enzyme- A protein that catalyzes chemical reactions within an organism.
• Active site- The region on an enzyme where the substrate bind during a
reaction.
• Substrate- The substance on which an enzyme acts to make a new product.
• Cofactors- Inorganic species or at least nonprotein compounds that aid
enzyme function by increasing the rate of catalysis. Typically, cofactors are
metal ions.
• Cosubstrates- These are coenzymes that bind tightly to a protein, yet will be
released and bind again at some point.
• Prosthetic groups- These are enzyme partner molecules that bind tightly
or covalently to the enzyme (coenzymes bind loosely). Prosthetic groups help
proteins bind other molecules, act as structural elements, and act as charge
carriers.

3. • Apoenzyme- It is the name given to an
inactive enzyme that lacks its coenzymes
or cofactors.
• Holoenzyme- It is the term used to
describe an enzyme that is complete with
its coenzymes and cofactors.
• Holoprotein- It is the word used for a
protein with a prosthetic group or
cofactor.

5. INTRODUCTION
• A coenzyme is defined as an organic molecule that binds to the active
sites of certain enzymes to assist in the catalysis of a reaction.
• It can be considered a helper molecule for a biochemical reaction.
• They are intermediate carriers of an atom or group of atoms, allowing
a reaction to occur.
• Coenzymes are not considered part of an enzyme's structure. They
are sometimes referred to as cosubstrates.
• Some enzymes require several coenzymes and cofactors.

7. FEATURES OF A COENZYME
1. Its an organic molecule
2. It is a small, non proteinaceous molecule
that provide a transfer site for a
functioning enzyme.
3. Coenzymes cannot function on their own
and require the presence of an enzyme.
4. Coenzymes, which are often vitamins or
derivatives of vitamins, therefore play a
crucial role in the regulation of most
enzyme activities
5. Like enzymes, it can be reused and
recycled.
ENZYME
COENZYME

8. HOW COENZYMES WORK ?

9. WHAT ARE THE FUNCTIONS OF
COENZYMES ??
• An enzyme without a coenzyme is called an
apoenzyme. Without coenzymes or cofactors,
enzymes cannot catalyze reactions effectively.
In fact, the enzyme may not function at all. If
the reactions cannot occur at the normal
catalyzed rate, then an organism will have
difficulty sustaining life.
• When an enzyme gains a coenzyme, it then
becomes a holoenzyme, or active enzyme.
These active enzymes change substrates into
the products, an organism needs to carry out
essential functions. They attach to a portion of
the active site on an enzyme, which enables the
catalyzed reaction to occur.

10. EXAMPLES OF COENZYMES
• During the conversion of pyruvate to acetyl coenzyme A (CoA), several
coenzymes including free CoA, thiamine pyrophosphate (TPP), lipoic
acid (LA), flavin adenine dinucleotide (FAD), two cellular redox
enzymes including oxidized nicotinamide adenine dinucleotide (NAD)
and reduced nicotinamide adenine dinucleotide (NADH) are required.
• The B vitamins serve as coenzymes essential for enzymes to form fats,
carbohydrates, and proteins.
• Adenosine triphosphate(ATP) is an example of an essential non-vitamin
coenzyme. It is the most widely distributed coenzyme in the human
body. It transports substances and supplies energy needed for
necessary chemical reactions and muscle contraction.

11. TPP(THIAMINE PYROPHOSPHATE)
• Thiamine pyrophosphate (TPP), the active
form of thiamine, functions as
a coenzyme for a number of enzymes
involved in carbohydrate metabolism , thus
making metabolites from this metabolism
and keto analogues from amino and fatty
acid metabolism available for the
production of energy.
• TPP can be found in various sources; yeast,
wheat, and sunflower seeds are considered
good sources of the vitamin, whereas dairy
products contain only small amounts.
• Increased losses and impaired biosynthesis
of TPP and can lead to various forms of
beriberi, a disease appearing mostly in
Southeast Asia.

12. FUNCTIONS OF TPP
• Enzymes carrying out decarboxylation and transketolation reactions, such
as the pyruvate dehydrogenase complex (PDH complex) and transketolase
rely on TPP as a catalytic cofactor.
• TPP acts catalytically in the decarboxylation of α-keto acids and the
transketolase reaction. In the mechanism of TPP-dependent enzymes, the
cofactor is a carrier of hydroxyalkyl residues (also referred to as "active
aldehydes")

13. COENZYME A(CoA)
• Coenzyme A, a helper molecule, is a
nonprotein chemical substance needed for
the activation of some enzymes, the
proteins that catalyze or activate important
chemical reactions within the body.
• Its notable for its role in the synthesis and
oxidation of fatty acids, and the oxidation
of pyruvate in the citric acid cycle.
• It is naturally synthesized from
pantothenic acid or vitamin B5
• Sources of vitamin B5 meat, vegetables,
legumes and milk.
• Coenzyme A and its derivatives can also be
successfully produced in chemical
laboratories.
STRUCTURE OF COENZYME A

14. FUNCTIONS OF CoA
1. Fatty Acid Synthesis
Coenzyme A is the helper molecule that facilitates the oxidation pathway.
Its an important chemical substance used for the initiation of fatty acid production
within the living cell. Without this much-needed process, there is no production of fatty
acids, the compounds that maintain the integrity of the cell membrane, the protective
covering of each living cell.
2. Drug and Enzyme Functioning
Coenzyme A improves the functioning of some proteins, sugars and drugs,
In drugs, it is used to extend a medication's half-life.
In cells, coenzyme A causes activation or inactivation of certain chemical compounds,
such as enzymes.
3. Energy Production
Coenzyme A, in the form of acetyl-coenzyme A, initiates the Krebs cycle, a chemical
process within the body that results in the production of carbon dioxide and adenosine
triphosphate
ATP is an important, energy-rich compound that provides fuel and energy needed for the
synthesis of protein and deoxyribonucleic acid.

16. FLAVIN MONONUCLEOTIDE(FMN)
• Flavin mononucleotide is a mononucleotide
also referred to as riboflavin-5′-
phosphate, riboflavin mononucleotide,
or vitamin B2 phosphate.
• Chemical formula: C17H21N4O9P
• It is a biomolecule derived from vitamin B2
(riboflavin) through the catalytic activity of
the enzyme riboflavin kinase.
• This means a phosphorylated vitamin B2 is
FMN.
• Word flavin is derived from the Latin
term flavus, for “yellow”. That is because
riboflavin comes from ribose and flavin,
which is the ring-moiety that imparts the
yellow color to the oxidized molecule. STRUCTURE OF FMN

17. • FMN is capable of acting as an oxidizing agent. Compared with a
common oxidizing agent NAD (nicotinamide adenine dinucleotide),
FMN is a stronger oxidizing agent.
• FMN can be found in tissues (e.g. muscles) and cells (e.g. erythrocytes
and platelets).
• The mononucleotide FMN may be converted to FAD (a dinucleotide)
trough the action of FAD pyrophosphorylase with ATP.
• FMN liberates free riboflavin, upon digestion.

18. FUNCTIONS OF FMN
• It assists certain oxidoreductases (e.g. NADH dehydrogenase) in various
oxidation-reduction reactions.
• It is also functions as a cofactor in blue-light photo receptors.
• This biomolecule is associated with the following biochemical pathways -
vitamin B6 metabolism, riboflavin metabolism, pyrimidine metabolism, beta-
alanine metabolism, arginine and proline metabolism, and pantothenate and
CoA biosynthesis.
• FMN forms certain flavoproteins when conjugated with certain proteins.
These proteins are essential in many biological processes, such as DNA
repair, bioluminescence, photosynthesis, and the removal of free radicals.
• FMN is used in food industry as food additive e.g. in milk product, sweets and
sugar products. It imparts an orange-red food color.

20. REFERENCES
• https://www.sciencedirect.com/
• https://www.thoughtco.com/
• https://www.biologyonline.com/
• https://www.youtube.com/