3. Introduction
• Fritz Albert Lipmann received the 1953
Nobel Prize in medicine or physiology “for
his discovery of coenzyme A (an important
catalytic substance in the cellular
conversion of food into energy) and its
importance for intermediary metabolism.
• Lipmann is credited with formulating the
general rules for the biotechnology of
energy transmission and was major
participant in deciphering the cellular,
catalytic, and energetic mechanisms
needed to understand how the body
builds and renews itself.
Fritz Albert Lipmann
(June 12,1899-July 24,1986)
4. Co-factor
A cofactor is a non protein chemical
compound that is required for the
protein ’s biological activity. These
proteins are commonly enzymes, and
cofactors can be considered “helper
molecules” that assist in biochemical
transformations.
Cofactors can be divided into two
broad groups: organic cofactors, such
as flavin or heme, and inorganic
cofactors, such as the metal ions
Mg2+ , Cu+,Mn2+, or iron-sulfur
clusters.
5. CO-ENZYMES
• Enzymes are conjugated proteins
• Enzymes (conjugated proteins) = Apo-enzyme
(inactive)
• The non protein part = Co-enzyme
• Apo-enzyme + Coenzyme = Holoenzyme
(active)
6. Apo-Enzyme and Co-Enzyme
• Coenzymes are a type of cofactor and they are bound
to enzyme’s active sites to aid with their proper
functioning.
• Coenzymes which are directly involved and altered in
the course of chemical reactions are considered to be
a type of secondary substrate.
• The non-protein part is called Co-enzyme.
• When tightly bound the Co-enzyme is called
Prosthetic-Group
7. Function of coenzyme
• The coenzyme is essential for the biological activity of
the enzyme.
• A coenzyme is a low molecular weight organic
substance, without which the enzyme cannot exhibit
any reaction.
• One molecule of the coenzyme is able to convert a
large number of substrate molecules with the help of
enzyme.
8.
9. Some important coenzymes
Transfer of group
other than H+
oPyridoxal Phosphate
oCo-enzyme A
oCobamide co-enzyme
B12
oLipoic Acid
Transfer of H+ group
oNAD+ , NADP+
oFMN , FAD
oLipoic Acid
10. Coenzyme A
• Coenzyme A is a prominent coenzyme of living organism which
transfers the acyl group of carboxylic acid.
• It plays an important role in the metabolism of
proteins,carbohydrates and fats which are important reactions that
allow the energy from food to be released. For example coenzyme
A is required for the oxidation of pyruvate in the citric acid cycle.
• Coenzyme A is also important in the synthesis of cholesterol and
steroid hormones, and is required for the detoxification of a range
of harmful drugs that can accumulate in the liver.
11. Nicotinamide Adenine Dinucleotide
(𝑵𝑨𝑫+
)
• NAD+ is composed of two nucleotide, adenine and
nicotinamide
• The nucleotides are held together by a pair of
phosphate groups which acts as bridge and are also
bonded to a ribose sugar each.
• The function of NAD+ is to carry electrons from one
enzyme controlled reaction to another.
• NAD+is involved with redox reaction because
substrates are either oxidized , in which they lose
electrons or are reduced in which they gain electrons.
12.
13. Nicotinamide Adenine Dinucleotide
Phosphate(NADP+)
• It is also known as
Coenzyme 2 or
phosphocoenzyme or TPN
(triphosphopyridine
nucleotide) or
codehydrogenase 2.
• It has one additional
phosphate group than DPN
molecule in position 2’ of
ribose molecule of
adenosine.
• It also helps in
Dehydrogenation.
14. Flavin Mono Nucleotide(FMN)
• It is also known as Riboflavin
phosphate.
• Riboflavin is a component of
this coenzyme. Another
name of this coenzyme is
riboflavin-5’-phosphate & it
combines with various
specific proteins
(apoenzymes) to form
enzymes e.g., L-amino acid
oxidase & cytochrome-C
reductase.
15. Flavin Adenine Dinucleotide (FAD)
• FAD is composed of an
adenine nucleotide, a
ribose sugar and two
phosphate groups.
• FAD can also exist as a
monophosphate and is
called flavin adenine
monophosphate (FMN).
• FAD is involved with redox
reactions.
• Like NAD, FAD can exist in
two redox states FAD and
FADH.
16. Vitamin B12 (cobalamin)
• Cobalamin contains Co(III)
coordinated to a corrin ring
• It is synthesized by only a
few microorganism and
Humans obtain cobalamin
from foods of animal
origin(deficiency leads to
pernicious anemia)
• Involved in synthesis of
DNA, amino acids, fatty
acids, one-C
metabolism(methylations).
Vitamin B12
17. Reference
Principle of Biochemistry, A.L. Lehninger,
Worth Publishers
Outlines of Biochemistry By Eric E. Conn
and P. K. Stumpf (Third Edition)
Principles of Bioinorganic Chemistry by
S.J. Lippard and J.M. Berg
