Source of NH3 for human body, Oxidative and Non-oxidative deaminations

Sources of NH3 for human body.
Oxidative and Non-oxidative deaminations
Biochemistry.

1. SOURCES OF AMMONIA, OXIDATIVE DEAMINATIONS, NON-OXIDATIVE DEAMINATIONS MARYAM JAMILAH BINTI ABDUL HAMID 082013100002 IMS BANGALORE

2. LEARNING OUTCOME Students should be able to list the source of NH 3 . Students should be able to understand the:- Oxidative deamination Non-oxidative deamination

3. SOURCES OF AMMONIA From amino acids From glutamine From bacterial action in the intestine From amines From purines and pyrimidines

4. From amino acids Oxidative deamination Non oxidative deamination Transamination followed by oxidative deamination

5. From glutamine

6. In intestine, intestinal glutaminase will hydrolyse the glutamine. *Intestinal glutamine metabolism produces citrulline , which travels to the kidney and is used to synthesize arginine (UREA CYCLE) From bacterial action in the intestine Ammonia is formed from urea by bacterial urease . This ammonia is absorbed by intestine and travels to liver via portal vein to be converted into urea before being excreted from body. From amines Amines can be obtained from diet Monoamines that serve as hormone and neurotransmitters These amines and monoamines can release ammonia by the action of amine oxidase

7. From bacterial action in the intestine

8. From amines From purines and pyrimidines Amino groups attached to the rings of purines and pyrimidines are released as ammonia

9. OXIDATIVE DEAMINATION

10. 1)GLUTAMATE DEHYDROGENASE To liberate amino group from amino acid as free ammonia Site: mitochondria in the liver Co-enzymes: NAD + or NADP +

11. Factors affecting the direction of reactions Concentration of glutamate Concentration of α - ketoglutarate Concentration of NH 3 Ratio of oxidised to reduced co-enzyme (NAD + and NADH)

12. Allosteric regulators Guanosine triphosphate (GTP) -inhibitor Adenosine diphosphate (ADP) -activator

13. 2)L-AMINO ACID OXIDASE Act on all amino acids EXCEPT hydroxy amino acids and dicarboxylic amino acids. H 2 O 2 will be decomposed by catalase in the peroxisomes

14. 3)D-AMINO ACID OXIDASE It can oxidise glycine and any D amino acid that may be formed by bacterial metabolism

15. 4)MONO AMINE OXIDASE Oxidation of monoamines by this enzyme will produce ammonia

16. DEHYDRATASES act on hydroxy amino acids Serine H 2 O

17. Desulfhydrase Cysteine

18. DEHYDRATASES (cont.) Threonine

19. serine,PLP =PYRIDOXAL PHOSPHATE (VIT B6), gves pyruvate In Threonine , it will be converted into alpha keto butyric acid Cysteine undergoes deamination and simultaneous transsulfuration to form pyruvate

20. Histidase

21. 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