TRANSDEAMINATION AND DEAMINATION

TRANSDEAMINATION
TRANSAMINATION
DEAMINATION

1. TRANSDEAMINATION AND
DEAMINATION
By:
Minhaz Ahmed
BBI11014
Int msc V sem
Tezpur university
Assam

2. CONTENT
•TRANSDEAMINATION
•TRANSAMINATION
•DEAMINATION

3. TRANSDEAMINATION
The amino group of amino acids is released by a
coupled reaction, TRANSDEAMINATION
Transamination followed by oxidative deamination.
Transamination takes place in the cytoplasm of all
the cells of the body : the amino group is transported
to liver as glutamic acid, which is finally oxidatively
deaminated in the mitochondria of hepatocytes.
Thus, the two components of the reaction are
physically far away, but phisiologically they are
coupled. Hence, Transdeamination.

4. •Transamination is a chemical reaction between two
molecules.
•One is an amino acid, which contains an amine (NH
2
)
group.
•The other is a keto acid, which contains a keto (=O)
group.
• In transamination, the NH
2
group on one molecule is
exchanged with the =O group on the other molecule. The
amino acid becomes a keto acid, and the keto acid
becomes an amino acid.
•Transamination in biochemistry is accomplished by
enzymes called transaminases or aminotransferases.

5. 5
Transamination
transfer of -NH
2 group from one substrate to other
•most AA (not Lys, Thr, Pro, His, Trp, Arg, Met)
•amino group is transferred from AA to 2-oxoglutarate
•cofactor – pyridoxal phosphate (® Schiff bases)
•reversible reaction Þ important for synthesis of AA

6. 6
General scheme of transamination
CH
2CH
2COOH
O
CHOOC+RCH
NH
2
COOH
aminokyselina 2-oxoglutarát
HOOCCHCH2CH2COOH
NH
2
+RC
O
COOH
glutamát2-oxokyselina
aminotransferasa
pyridoxalfosfát
amino acid
2-oxo acid
2-oxoglutarate
glutamate
aminotransferase
pyridoxal phosphate

7. DEAMINATION
•Deamination is the removal of an amine group from
a molecule. Enzymes which catalyse this reaction are
called deaminases.
•In the human body, deamination takes place
primarily in the liver, however glutamate is also
deaminated in the kidneys.
•Deamination is the process by which amino acids are
broken down if there is an excess of protein intake.
The amino group is removed from the amino acid
and converted to ammonia.

8. Deamination of amino acids
•Deamination - elimination of amino group
from amino acid with ammonia formation.
• Four types of deamination:
• - oxidative (the most important for higher
animals),
• - reduction,
• - hydrolytic, and
• - intramolecular

9. Reduction deamination:
R-CH(NH
2
)-COOH + 2H
+
® R-CH
2
-COOH + NH
3
amino acid fatty acid
Hydrolytic deamination:
R-CH(NH
2
)-COOH + H
2
O ® R-CH(OH)-COOH +
NH
3
amino acid hydroxyacid
Intramolecular deamination:
R-CH(NH
2
)-COOH ® R-CH-CH-COOH + NH
3
amino acid unsaturated fatty acid

10. During oxidative deamination, an amino acid is 
converted into the corresponding keto acid by the 
removal of the amine functional group as ammonia.
The amine functional group is replaced by the ketone 
group. The ammonia eventually goes into the urea 
cycle.
Oxidative deamination occurs primarily on glutamic 
acid because glutamic acid was the end product of 
many transamination reactions.
The glutamate dehydrogenase is controlled by ATP and 
ADP. ATP acts as an inhibitor whereas ADP is an 
activator.

12. 12
Proteins
NH
3
glutamate
glutamate + urea
(excretion by urine)
2-oxoglutarate +
glutamine
proteolysis
dehydrogenation + deamination
detoxication in liver
deamidation
in kidney
amino acids
transamination
detoxication
in other tissues
NH
4
+
(excretion by urine)
NH
4
+
(excretion by urine)
deamination
in kidney
Intake, catabolism, and excretion of nitrogen

13. THANK YOU