The process of deamination and decarboxylation. Summarized in one presentation.

1. DEAMINATION AND
DECARBOXYLATION
Prepared by : Rabia Khan Baber
Course Title : Biochemistry

2. AIMS AND OBJECTIVES OF PPT
What is deamination?
Why does deamination occur?
Types of deamination
Importance of oxidative deamination
Types of non oxidative deamnation
Difference between oxidative and non-oxidative deamination
What is decarboxylation?
What are biogenic amines?
Importance of biogenic amines
Classification of biogenic amines, their importance and functions
Summary

3. AMINO ACID METABOLISM
 The general ways of amino acids degradation :
1. Transamination
2. Deamination
3. Decarboxylation

4. DEAMINATION
When an oversupply of nitrogen in the form of amino acids exists, it
needs to be disposed of somewhere in the body. Deamination is the
process that carries out this breakdown of amino acids. However, this
process releases free cytotoxic ammonia which has to be quickly
metabolized to urea. This urea synthesis, which requires a lot of energy,
takes place in the liver. For this to happen, the excess nitrogen needs to
be transported from the periphery to the liver.

5. WHY DOES DEAMINATION OCCUR ?
Deamination occurs when an excess in protein is consumed, resulting in
the removal of an amine group, which is then converted into ammonia
and expelled via urination. This deamination process allows the body to
convert excess amino acids into usable by-products.

6. TYPES OF DEAMINATION
There are two types of deamination.
i. OXIDATIVE
DEAMINATION
ii. NON-OXIDATIVE
DEAMINATION

7. OXIDATIVE DEAMINATION
Oxidative deamination is the process of removal of an amine group
from a molecule via oxidation. This type of reactions largely occurs in
liver and kidney. It involves the generation of alpha-keto acids and some
other oxidized products from amine groups. This reaction is very
important in the catabolism of amino acids. It forms a catabolized
product from amino acids. the byproduct of this reaction is ammonia
which is a toxic byproduct. Here, the amine group converts into
ammonia. And then, this ammonia converts into urea and excreted from
our body.

8. IMPORTANCE OF OXIDATIVE
DEAMINATION
Central Role for Glutamic Acid:
Apparently most amino acids may be deaminated but this is a significant
reaction only for glutamic acid. If this is true, then how are the other
amino acids deaminated? The answer is that a combination of
transamination and deamination of glutamic acid occurs which is a
recycling type of reaction for glutamic acid. The original amino acid
loses its amine group in the process.

9. NON OXIDATIVE DEAMNATION
Non-oxidative deamination is the process of removal of an amine group
from a molecule via different reactions other than oxidation. We call it
“direct deamination” without oxidation. There are certain reactions which
can be non-oxidatively deaminated by specific enzymes and can form
NH3. these reactions do not fulfil major role in NH3 formation.

10. Only three types of non oxidative deamnation will be discussed.
i. Amino acid dehydrases
ii. Deamination of histidine
iii. Amino acid desulfhydrases

11. DIFFERENCE BETWEEN OXIDATIVE
AND NONOXIDATIVE DEAMINATION

12. DECARBOXYLATION
Decarboxylation is the reaction in which the carboxyl group COOH is
removed from the amino acid and as a result amine is formed. It is
catalyzed by decarboxylases, pyridoxal phosphate-containing enzymes,
present in microorganisms and animal tissues. Intestinal bacteria
especially, have enzymes which can decarboxylate lysine and ornithine
respectively into cadaverine and putrescine, amines which are always
present in small quantities in the intestine, but can cause intoxications if
their concentration increases due to abnormal intestinal fermentations.

13. WHAT ARE BIOGENIC AMINES ?
Amines are formally derivatives of ammonia, wherein one or more
hydrogen atoms have been replaced by a substituent.
A group of Naturally Occurring, Biologically Active Amines, such as
norepinephrine, histamine and serotonin, that act primarily as
neurotransmitters and are capable of affecting mental functioning and
of regulating blood pressure, body temperature and other bodily
processes are called Biogenic Amines.
Biogenic amine occurs as a result of the enzymatic reaction catalyzed
by pyridoxal phosphate to decarboxylate the amino acid

14. IMPORTANCE OF BIOGENIC AMINES
Biogenic amines play an essential role in cell membrane stabilization,
immune functions, and prevention of chronic diseases, as they
participate in the nucleic acid and protein synthesis. Besides, they are
compounds created as the growth regulation neural transmission and
inflammation mediators.

15. CLASSIFICATION OF BIOGENIC
AMINES
ii. On The Basis Of
Amine Group
Biogenic amines are classified in two categories ;
i. On The Basis Of
Chemical Structure

16. ON THE BASIS OF CHEMICAL
STRUCTURE
i. Aromatic and Heterocyclic
ii. Aliphatic di-, tri-, and Polyamines
iii. Aliphatic Volatile Amines

17. Aromatic and
heterocyclic
amines
Amino acid
precursors
Aliphatic
precursor
Amino acid
precursors
Aliphatic
volatile amines
Amino acid
precursors
Histamine Histadine Putrescine Ornithine Ethanolamine Serine
Tryptamine Histadine Cadaverine Lysine Methylamine
Tyramine Tyrosine Agmatine Arginine Isopentylamine
Serotonin Tryptophan Spermine Ornithine Ethylamine L-Alanine

18. Monoamine Diamine Polyamine
Tyramine Histamine Spermine
Ethylamine Tryptamine Spermidine
Ethanolamine Serotonin Agmatine
ON THE BASIS OF AMINE GROUP

20. SOME OF THE IMPORTANT
BIOGENIC AMINES
Tyramine and its functions ;
Tyramine, consisting of tyrosine amino acid as a result of tyrosine
decarboxylase activity, is generally found in low amounts. Tyramine
leads to several physiological reactions such as blood pressure increase,
vasoconstriction, tyramine active noradrenalin secretion, etc., as the
sympathetic nervous system controls several functions of the body.
Tyramine, stored in the neurons, causes the increase in the tear,
salivation and respiratory as well as mydriasis

21. Tryptamine and its functions;
Tryptamine consists of tryptophan amino acid as a result of the aromatic
L-amino acid decarboxylase activity. Tryptamine is a monoamine
alkaloid found in plants, fungi, and animals. Tryptamine, found in trace
amounts in mammalian brains, increases blood pressure as well as plays
a role as a neurotransmitter or neuromodulator.
Histamine and its functions;
Histamine, a standard component of the body, consists of histidine
amino acid as a result of histidine decarboxylase activity depending on
pyridoxal phosphate. Histamine distribution and concentration found in
the tissues of all vertebrates are very unsteady . Histamine participates
in the essential functions such as neurotransmission and vascular
permeability. However, it also plays a role in starting the allergic
reactions.

22. Putrescine and its functions;
It consists of ornithine amino acid as a result of ornithine decarboxylase
activity. Putrescine, produced by bacteria and fungi, contributes to the
cell growth and cell division.
Spermine and its functions;
Whose precursor amino acid is ornithine, is formed from spermidine
through the spermine synthase enzyme .Spermine is present in several
organisms and tissues, as it is a polyamine that is found in all eukaryotic
cells and has a role in the cellular metabolism. It plays a role in the
intestinal tissue developments and stabilizes the helical structure in
viruses

24. SUMMARY
Deamination is the liberation of ammonia via the deamination of an
amine group. There are two major types of oxidative and nonoxidative
deamination. The nonoxidative deamination includes reactions other
than oxidation such as reduction, hydrolysis, and intramolecular
reactions. Hence, the key difference between oxidative and nonoxidative
deamination is that the oxidative deamination occurs via the oxidation
of amino group amino acids whereas the nonoxidative deamination
occurs via reactions other than oxidation.
Decarboxylation is a chemical reaction that removes a carboxyl group
and releases carbon dioxide (CO2). Usually, decarboxylation refers to a
reaction of carboxylic acids, removing a carbon atom from a carbon
chain.

25. REFERENCES
 Text book of medical biochemistry, MN Chatterjee
 Fundamentals of biochemistry, J.L Jain, Sunjay Jain, Nitin Jain