SOURCES OF AMMONIA,OXIDATIVE DEAMINATIONS,

NON-OXIDATIVE DEAMINATIONS

MARYAM JAMILAH BINTI ABDUL HAMID082013100002

IMS BANGALORE

LEARNING OUTCOME

• Students should be able to list the source of

NH3.

• Students should be able to understand the:-

Oxidative deamination

Non-oxidative deamination

SOURCES OF AMMONIA

1. From amino acids

2. From glutamine

3. From bacterial action in the intestine

4. From amines

5. From purines and pyrimidines

From amino acids

• Oxidative deamination

• Non oxidative deamination

• Transamination followed by oxidative

deamination

From glutamine

From bacterial action in the intestine

From amines

From purines and pyrimidines

• Amino groups attached to the rings of purines and

pyrimidines are released as ammonia

OXIDATIVE DEAMINATION

Oxidative deamination

Major pathway

Glutamate

dehydrogenas

e

D-Amino acid

oxidase

Minor pathway

L-Amino acid oxidase

Mono amine oxidase

1)GLUTAMATE DEHYDROGENASE

• To liberate amino

group from amino acid

as free ammonia

• Site: mitochondria in

the liver

• Co-enzymes: NAD+ or

NADP+

Factors affecting thedirection of reactions1. Concentration of

glutamate2. Concentration of α-

ketoglutarate3. Concentration of

NH3

4. Ratio of oxidised to reduced co-enzyme(NAD+ and NADH)

Allosteric regulators

1. Guanosine triphosphate (GTP) -inhibitor

2. Adenosine diphosphate (ADP) -activator

2)L-AMINO ACID OXIDASE

• Act on all amino acids EXCEPT hydroxy amino acids and

dicarboxylic amino acids.

• H2O2 will be decomposed by catalase in the peroxisomes

3)D-AMINO ACID OXIDASE

• It can oxidise glycine and any D amino acid

that may be formed by bacterial metabolism

4)MONO AMINE OXIDASE

• Oxidation of monoamines by this enzyme will produce ammonia

Non-oxidative deamination

DehydratasesDesulfhydrase

Histidase

DEHYDRATASES

• act on hydroxy amino acids

Serine

H2O

Desulfhydrase

Cysteine

DEHYDRATASES (cont.)

Threonine

Histidase

REFERENCES

• Lippincott’s Illustrated Reviews: Biochemistry Fifth Edition, Richard A. Harvey, PhD and Denise R. Ferrier, PhD, Lippincott Williams & Wilkins, Philadelphia, USA.

• Vasudevan, D., S, S., & Vaidyanathan, K. (2013).Textbook of biochemistry for medical students. (7th ed., pp. 202-203). New Delhi: Jaypee Brothers Medical Publishers (P) Ltd.

• http://www.omicsgroup.org/journals/damino-acid-oxidase-and-metagenomics-2168-9849.1000111.php?aid=17328