Cofactors and coenzymes are organic or inorganic molecules that assist enzymes in catalyzing biochemical reactions. There are two main types of cofactors - inorganic ions that are tightly bound and function as enzyme activators, and organic compounds that exist as coenzymes or prosthetic groups. Coenzymes are loosely bound organic molecules that serve as carriers, transferring chemical groups between enzymes and allowing redox and group transfer reactions. Many coenzymes are derived from vitamins and help mediate important metabolic reactions.

2. Cofactors:
Inorganic substances like metal ions that are required to increase the rate of
catalysis.
Chemical compunds or elements associated with the enzyme to increase its
efficiency.
There are mainly two types- inorganic ions and organic compounds.
Inorganic ions: Known as enzyme activators (Cl ion in salivary amylase).
Organic compunds: Divided into two types- co-enzymes and prosthetic groups.

3. cofactor enzyme or protein
Zn++ carbonic anhydrase, alcohol dehydrogenase
Fe+++ or
Fe++
cytochromes, hemoglobin, ferredoxin
Cu++ or
Cu+
cytochrome oxidase
K+ and
Mg++
pyruvate phosphokinase

4. Coenzymes:
Cofactors that are bound to an enzyme loosely.
Non protein organic/ metallo organic molecules.
Non covalently/covalently attached to the enzyme.
Special case of cofactors. (With Prosthetic groups)
Can be removed from the enzyme & undergo cyclic reactions to combine with
enzyme (EX: NAD, NADP)

5. VITAMIN COENZYME RxN MEDIATED
NIACIN nicotine adenine dinucleotide, nicotine adenine dinucelotide
phosphate (NADH,NADHP-Partly composed of niacin)
OXIDATION-REDUCTION RxN
electron (hydrogen atom) transfer
RIBOFLAVIN
(VITAMIN B2)
flavine adenine dinucleotide(FADH,FAD+ Partly composed of
riboflavin - vit. B2)
OXIDATION-REDUCTION RxN
electron (hydrogen atom) transfer
PANTOTHENATE
(PANTOTHENIC
ACID)
coenzyme A Acyl groups activation & transfer
Co-Q10 coenzymeQ10 OXIDATION-REDUCTION RxN
electron (hydrogen atom) transfer
THIAMINE
(VITAMIN B1)
thiamine pyrophosphate Activation & transfer of aldehydes
(carbonyl groups)
PYRIDOXINE
(VITAMIN B6)
pyridoxal phosphate Amino acids activation & amino groups
transfer

6. VITAMIN COENZYME RxN MEDIATED
COBALAMIN (VITAMIN
B12)
Carbamide coenzymes Alkyl groups / alkylation RxN
(Isomerization & Methyl group transfer)
BIOTIN biotin CARBOXYLATION RxN (carbon dioxide
activation & transfer)
NICOTINAMIDE nicotinamide OXIDATION-REDUCTION RxN
electron (hydrogen atom) transfer
FOLIC ACID tetrahydrofolate Activation & transfer of single carbon
groups.
LIPOIC ACID lipoamide Acylgroup activation & transfer
OXIDATION-REDUCTION RxN

7. Cofactor Coenzyme
Definition It is a non-protein chemical
compounds that are bound
tightly or loosely to an enzyme
or other protein molecules.
It is defined as small, organic,
non-protein molecules, which
carry chemical groups between
enzymes.
Molecule type These are organic as well as
inorganic compounds /
substances.
These are organic molecules /
substances.
Function It assists in biological
transformations.
It aids or helps the function of an
enzyme or the relative enzyme.
Type They are chemical compounds.
Two types of cofactors are:
They are chemical molecules,
include under type of cofactor.

8. Cofactor Coenzyme
Binding
strength
It is loosely or tightly bound
that is covalently bound to an
enzyme.
It is loosely bound to an enzyme.
Action They act on catalyst to increase
the speed of the reaction.
They act as carries to the
enzymes.
Role They increase the rate of the
reaction that is catalyzed by the
relevant enzyme.
They serve as carriers to the
enzymes.
Removal They can only be removed by
denaturing the enzyme.
They can be removed from the
enzyme easily since they are
loosely bound to the enzyme.

9. Cofactor Coenzyme
Characteristic Its presence is important for
the activity of an enzyme.
They bind with an enzyme to
catalyze a reaction.
Example Metal Ions like Zn++, K+
and Mg++, etc.
Vitamins, Biotin, Coenzyme A, etc

10. TERMINOLOGY
PROSTHETIC GROUPS
Co factors /co enzymes that are tightly bound to the enzyme molecules(EX : FAD).
TURNOVER RATE
The number of substrate molecules acted upon by an enzyme in one second under appropriate conditions.
INTERNATIONAL UNIT
Amount of enzyme causing Transformation of 1μmol of substrate/minute under optimal conditions.
APOENZYME
Protein component of enzyme.
HOLOENZYME
Apoenzyme + non protein component.

11. TERMINOLOGY
ACTIVE SITE
Special pocket or cleft in an enzyme molecule. Has amino acid side chains for substrate binding &catalysis.
ALLOSTERIC SITES
Enzymes have allosteric sites(other than active site) where effectors (chemical reagents acting as modifiers) bindthrough non
covalent linkage.
ACTIVITY
Total units of enzymes in a given solution.
SPECIFIC ACTIVITY
Number of enzyme units/mg of total protein.
KATAL
Amount of an enzyme which catalyzes a reaction rate of 1 mole of substrate / second.
SUBSTRATE
The substance upon which an enzyme acts is called the substrate.

12. Reference:
1. Helmenstine, Ph.D. Anne Marie. “What Is a Coenzyme? Definition and
Examples.” ThoughtCo. N.p., n.d. <https://www.thoughtco.com/definition-of-
coenzyme-and-examples-604932>.
2. “Cofactor.” Encyclopædia Britannica. Encyclopædia Britannica, inc., n.d. Web.
<https://www.britannica.com/science/cofactor>.
3. “Coenzymes and cofactors.” Coenzymes and cofactors. N.p., n.d. Web.
<http://academic.brooklyn.cuny.edu/biology/bio4fv/page/coenzy_.htm>.
4. J.H. Freeland-Graves, C. Bavik, in Encyclopedia of Food Sciences and Nutrition
(Second Edition), 2003

13. Thank You