1. Serine,Alanine one Carbon Metabolism
Dr. Ketki K Assistant Professor Dept of Biochemistry
HIMS Varanasi

2. Serine
Aliphatic hydroxy amino acid
Non essential
Glucogenic

3. Sources of Serine:
Phosphoglycerate
Glycine ( glycine → serine)
Alanine + hydroxypyruvate → Pyruvate Serine

5. Catabolism of serine
Deamination to Pyruvate
Transamination to hydroxypyruvate
Serine is glucogenic

7. Metabolic functions of Serine
1) One carbon pool (serine → glycine)
2) Formation of cysteine
(homocysteine + serine → homoserine + cysteine)
3) Serine → alanine by dehydration & transamination
4) Phosphotidyl serine
5) Used as drug: eg, Azaserine- anticancer drug,
Cycloserine- antituberculous drug

8. 6) Choline synthesis: Serine → ethanolamine → choline Used for acetylcholine synthesis(Neurotransmitter), From choline , 3 carbons can be removed, important one carbon donor (salvage pathway for one carbon unit)

10. 7) Serine as a component of Protein
Phosphoprotein: eg, Casein
In covalent modification
Glycoproteins
Active group of enzymes:
eg: serine proteases : Trypsin,coagulation factor

11. Alanine Non essential Glucogenic
Pyruvate + glutamate → alanine + alpha keto gluterate (transamination,PLP dependant)
C/S: 1) ALT: Increased in liver disease
2) Major important participant in inter
organ transport of nitrogen
(glucose alanine cycle)

12. One carbon metabolism Content
One carbon compounds
Generation of one carbon compounds
Inter-conversion of one carbon compounds
Utilization of one carbon compounds

13. One carbon metabolism
Role in donating carbon atom for synthesis of several compounds
One carbon pool of the body:

15. Generation of one carbon compounds
From amino acids
Serine
Glycine
Histidine
Tryptophan
Choline( salvage pathway for one carbon unit)

21. Inter-conversion of one carbon compounds
Important irreversible step: reductase
Folate trap

23. Utilization of one carbon compounds
For synthesis of
C2 of Purine
Formylation of methionyl tRNA
C8 of Purine
Glycine (glycine synthase complex)
Serine ( glycine to serine)
Choline ( ethanolamine to choline)
Deoxy TMP ( dUMP tp dTMP)
Transmethylation reactions
Excreted as CO2