The document discusses vitamin B6 and its role in amino acid metabolism. It covers the history, sources, structures and isoforms of vitamin B6. The key active forms are pyridoxal phosphate and pyridoxamine phosphate. Vitamin B6 is required for important amino acid reactions like transamination and deamination. Transamination reactions involve the interconversion of amino acids and alpha-keto acids using vitamin B6 as a cofactor. They are important for synthesizing non-essential amino acids and recycling carbon skeletons. Deamination reactions remove amino groups from amino acids, producing ammonia, and use vitamin B6 cofactors.

1. Biochemistry For Medics
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1Biochemistry for medics- Namrata Chhabra

2. 2Biochemistry for medics- Namrata Chhabra

3.  Introduction to Vitamin B6
 Structure of Vitamin B6
 Activation of Vitamin B6
 Role in Amino Acid Metabolism
Overview of Seminar
 General Amino Acid Reactions
 Metabolism of Tryptophan
 Metabolism of Methionine
 Metabolism of Glycine
3Biochemistry for medics- Namrata Chhabra

4.  Introduction to Vitamin B6
 Structure of Vitamin B6
 Activation of Vitamin B6
 Role in Amino Acid Metabolism
Overview of Seminar
 General Amino Acid Reactions
 Metabolism of Tryptophan
 Metabolism of Methionine
 Metabolism of Glycine
4Biochemistry for medics- Namrata Chhabra

5. B-Complex Vitamins
 Water Soluble Vitamins
 Earlier thought of as being a Single Vitamin
 Later found to be composed of EIGHT Chemically distinct Vitamins
Vitamin B1 (Thiamine)
Vitamin B2 (Riboflavin)
Vitamin B3 (Niacin)
Vitamin B5
(Pantothenic Acid)
Vitamin B6
Vitamin B7 (Biotin)
Vitamin B9 (Folic Acid)
Vitamin B12
(Cobalamin)
INTRODUCTIO
N:
5Biochemistry for medics- Namrata Chhabra

6. B-Complex Vitamins
 Water Soluble Vitamins
 Earlier thought of as being a Single Vitamin
 Later found to be composed of EIGHT Chemically distinct Vitamins
Vitamin B1 (Thiamine)
Vitamin B2 (Riboflavin)
Vitamin B3 (Niacin)
Vitamin B5
(Pantothenic Acid)
Vitamin B6
Vitamin B7 (Biotin)
Vitamin B9 (Folic Acid)
Vitamin B12
(Cobalamin)
Vitamin B6
INTRODUCTIO
N:
6Biochemistry for medics- Namrata Chhabra

7. B-Complex Vitamins
INTRODUCTIO
N:  Water Soluble Vitamins
 Earlier thought of as being a Single Vitamin
 Later found to be composed of EIGHT Chemically distinct Vitamins
Vitamin B1 (Thiamine)
Vitamin B2 (Riboflavin)
Vitamin B3 (Niacin)
Vitamin B5
(Pantothenic Acid)
Vitamin B6
Vitamin B7 (Biotin)
Vitamin B9 (Folic Acid)
Vitamin B12
(Cobalamin)
Vitamin B6
7Biochemistry for medics- Namrata Chhabra

8. HISTOR
Y:
Introduction
 Discovered in 1934
 Hungarian physician, Paul György
 Ability to cure Dermititis Acrodynia in Rats
 Isolated in 1938
 Polish nutritionist, Samuel Lepkovsky
 Isolated from Rice Bran
 Structure of Pyridoxine in 1939
 Harris and Folkers
 Structure of Pyridoxal and Pyridoxamine in 1945
 American Biochemist, Esmond Snell
8Biochemistry for medics- Namrata Chhabra

9. GOOD
SOURCES
Sources of Vitamin B6
 Vitamin B6 is ABUNDANTLY present in:
 Royal Jelly of Bees
 Yeast
 Rice Polishing
 Cereal Grains
 Egg Yolk
 Germinal portion of various Seeds
MODERATE
SOURCES
 Vitamin B6 is MODERATELY present in:
 Liver
 Kidney
 Muscle
 Fish
POOR
SOURCES
 Vitamin B6 is POORLY present in:
 Milk
9Biochemistry for medics- Namrata Chhabra

10. Structure
 Derivatives of Pyridine Ring
Pyridine Ring
10Biochemistry for medics- Namrata Chhabra

11. Structure
 Derivatives of Pyridine Ring
Purine RingPyridoxine
2-Methly, 3-Hydroxy, 4,5-diHydroxyMethly Pyridine
 Pyridoxine
11Biochemistry for medics- Namrata Chhabra

12. Structure
 Pyridoxal
Purine RingPyridoxal
12Biochemistry for medics- Namrata Chhabra

13. Structure
 Pyridoxamine
Purine RingPyridoxamine
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14. Structure
 Derivatives of Pyridine
 Pyridoxine
 Also known as Pyridoxol
 4th position contains a CH2OH group
 Precursor from of Vitamin B6
 Plant in origin Pyridoxine
Pyridoxal
Pyridoxamine
 Pyridoxal
 4th position contains a CHO group
 Precursor from of Vitamin B6
 Plant in origin
 Pyridoxamine
 4th position contains a CH2NH2 group
 Precursor from of Vitamin B6
 Plant in origin
14Biochemistry for medics- Namrata Chhabra

15. Structure
 Biochemically active only when Phosphorylated
 Phosphorylation is brought about by Kinase enzyme
 Phosphorylation occurs at 5th Position
Pyridoxine Pyridoxine-P (Phosphate)
Kinase
15Biochemistry for medics- Namrata Chhabra

16. Structure
 Pyridoxine
 Also known as Pyridoxol
 4th position contains a CH2OH group
 Precursor from of Vitamin B6
 Plant in origin
 Pyridoxal
 4th position contains a CHO group
 Precursor from of Vitamin B6
 Plant in origin
 Pyridoxamine
 4th position contains a CH2NH2 group
 Precursor from of Vitamin B6
 Plant in origin
Pyridoxine
Pyridoxal
Pyridoxamine
16Biochemistry for medics- Namrata Chhabra

17. Structure
Pyridoxine
Pyridoxal
Pyridoxamine
Pyridoxine-P
Pyridoxal-P
Pyridoxamine-P
Kinase
Kinase
Kinase
17Biochemistry for medics- Namrata Chhabra

18. Structure
 Biochemically active only when Phosphorylated
 Phosphorylation is brought about by Kinase enzyme
 Phosphorylation occurs at 5th Position
 In total, there are 6 isoforms of Vitamin B6:
Pyridoxine Pyridoxine-P (Phosphate)
 Pyridoxine
 Pyridoxine-P
 Pyridoxal
 Pyridoxal-P
 Pyridoxamine
 Pyridoxamine-P
18Biochemistry for medics- Namrata Chhabra

19. Structure
 Biochemically active only when Phosphorylated
 Phosphorylation is brought about by Kinase enzyme
 Phosphorylation occurs at 5th Position
 In total, there are 6 isoforms of Vitamin B6:
 Pyridoxine
 Pyridoxine-P
 Pyridoxal
 Pyridoxal-P
 Pyridoxamine
 Pyridoxamine-P
 Pyridoxic Acid
 Excretory form of Vitamin B6
 Oxidation at 4th position
Pyridoxic Acid
NOTE: Vitamin B6 can also be excreted
in the UNCHARGED form as Pyridoxine or
Pyridoxal
19Biochemistry for medics- Namrata Chhabra

20. Structure
 Biochemically active only when Phosphorylated
 Phosphorylation is brought about by Kinase enzyme
 Phosphorylation occurs at 5th Position
 In total, there are 6 isoforms of Vitamin B6:
 Pyridoxine
 Pyridoxine-P
 Pyridoxal
 Pyridoxal-P
 Pyridoxamine
 Pyridoxamine-P
 Pyridoxic Acid
 Excretory form of Vitamin B6
 Oxidation at 4th position
Pyridoxic Acid
NOTE: Vitamin B6 can also be excreted
in the UNCHARGED form as Pyridoxine or
Pyridoxal
20Biochemistry for medics- Namrata Chhabra

21. Activation of Vitamin B6
 Biologically active forms are: a) Pyridoxal-PO4
b) Pyridoxamine-PO4
Pyridoxine Pyridoxal
Pyridoxal-P
Dehydrogenase
Pyridoxal Kinase
H2
ATP
ADP
Zn2+
Mg2+
21Biochemistry for medics- Namrata Chhabra

22. Role in Amino Acid Metabolism
 Absorption is by either PASSIVE or ACTIVE mechanisms
 Vitamin B6 is absorbed by ACTIVE TRANSPORT
 Amino Acid Absorption
22Biochemistry for medics- Namrata Chhabra

23. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Transamination Reactions
 SGPT (Serum Glutamate Pyruvate Transaminase)
Glutamate Pyruvate
23Biochemistry for medics- Namrata Chhabra

24. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Transamination Reactions
 SGPT (Serum Glutamate Pyruvate Transaminase)
Glutamate Pyruvate
24Biochemistry for medics- Namrata Chhabra

25. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Transamination Reactions
 SGPT (Serum Glutamate Pyruvate Transaminase)
Glutamate PyruvateAlanine α-keto Glutarate
25Biochemistry for medics- Namrata Chhabra

26. Role in Amino Acid Metabolism
Pyridoxal-P
Pyruvic Acid
(Recipient α-keto acid)
Glutamate
(Donor α-amino acid)
Mechanism of Reaction
26Biochemistry for medics- Namrata Chhabra

27. Role in Amino Acid Metabolism
Pyridoxal-P
Pyruvic Acid
(Recipient α-keto acid)
Glutamate
(Donor α-amino acid)
Mechanism of Reaction
27Biochemistry for medics- Namrata Chhabra

28. Pyridoxal-P
Glutamate
(Donor α-amino acid)
Role in Amino Acid Metabolism
Pyridoxal-P
Pyruvic Acid
(Recipient α-keto acid)
Glutamate
(Donor α-amino acid)
α-keto Glutarate
(New α-keto acid) Pyridoxamine-P
Mechanism of Reaction
28Biochemistry for medics- Namrata Chhabra

29. Pyruvic Acid
(Recipient α-keto acid)
Role in Amino Acid Metabolism
Pyridoxal-P
Pyruvic Acid
(Recipient α-keto acid)
Glutamate
(Donor α-amino acid)
α-keto Glutarate
(New α-keto acid) Pyridoxamine-P
Alanine
(New α-amino acid)
Pyridoxal-P
Mechanism of Reaction
29Biochemistry for medics- Namrata Chhabra

30. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Transamination Reactions
 SGPT (Serum Glutamate Pyruvate Transaminase)
α-keto Glutarate
(New α-keto acid)
Alanine
(New α-amino acid)
Pyruvate
(Recipient α-keto acid)
Glutamate
(Donor α-amino acid)
SGPT
B6-P
+ +
30Biochemistry for medics- Namrata Chhabra

31. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Transamination Reactions
 SGPT (Serum Glutamate Pyruvate Transaminase)
α-keto Glutarate
(New α-keto acid)
Alanine
(New α-amino acid)
Pyruvate
(Recipient α-keto acid)
Glutamate
(Donor α-amino acid)
SGPT
B6-P
+ +
31Biochemistry for medics- Namrata Chhabra

32. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Transamination Reactions
 SGPT (Serum Glutamate Pyruvate Transaminase)
Pyruvate + Glutamate Alanine + α-keto Glutarate
 SGOT (Serum Glutamate Oxaloacetate Transaminase)
Oxaloacetate + Glutamate Aspartate + α-keto Glutarate
CLINICAL SIGNIFICANCE
 Synthesis of Non-Essential Amino Acids
 Alanine
 Aspartate
 Recycling of Carbon Skeletons
 Pyruvate
 Oxaloacetate
32Biochemistry for medics- Namrata Chhabra

33. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Transamination Reactions
 SGPT (Serum Glutamate Pyruvate Transaminase)
Pyruvate + Glutamate Alanine + α-keto Glutarate
 SGOT (Serum Glutamate Oxaloacetate Transaminase)
Oxaloacetate + Glutamate Aspartate + α-keto Glutarate
CLINICAL SIGNIFICANCE
 Synthesis of Non-Essential Amino Acids
 Alanine
 Aspartate
 Recycling of Carbon Skeletons
 Pyruvate
 Oxaloacetate
33Biochemistry for medics- Namrata Chhabra

34. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Deamination Reactions
 Non-Oxidative Deamination
Serine
34Biochemistry for medics- Namrata Chhabra

35. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Deamination Reactions
 Non-Oxidative Deamination
Dehydrase
H2O
B6-P
H2ONH3
Serine Imino Acid
Pyruvate
Imino Acid
35Biochemistry for medics- Namrata Chhabra

36. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Deamination Reactions
 Non-Oxidative Deamination
Dehydrase
H2O
B6-P
H2ONH3
Serine Imino Acid
Pyruvate
Imino Acid
36Biochemistry for medics- Namrata Chhabra

37. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Deamination Reactions
 Non-Oxidative Deamination
 Serine Deamination
 Cysteine Deamination
Serine
Cysteine
Pyruvate
Pyruvate
Water
Hydrogen Sulphide
+
+
Dehydrase
B6-P
Desulfhydrase
B6-P
CLINICAL SIGNIFICANCE  Breakdown of excess amino acids in Liver
 Contributes to NH3 formation in the body
NH3
NH3
37Biochemistry for medics- Namrata Chhabra

38. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Deamination Reactions
 Non-Oxidative Deamination
 Serine Deamination
 Cysteine Deamination
Serine
Cysteine
Pyruvate
Pyruvate
Water
Hydrogen Sulphide
+
+
Dehydrase
B6-P
Desulfhydrase
B6-P
CLINICAL SIGNIFICANCE  Breakdown of excess amino acids in Liver
 Contributes to NH3 formation in the body
NH3
NH3
38Biochemistry for medics- Namrata Chhabra

39. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Interconversion of Amino Acids
 Racemases
 Conversion of L-amino Acids to D-Amino Acids
 Conversion of D-Amino Acids to L-Amino Acids
RACEMASE
B6-P
L-AlanineD-Alanine
39Biochemistry for medics- Namrata Chhabra

40. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Interconversion of Amino Acids
 Racemase
 Conversion of L-amino Acids to D-Amino Acids
 Conversion of D-Amino Acids to L-Amino Acids
RACEMASE
B6-P
L-AlanineD-Alanine
40Biochemistry for medics- Namrata Chhabra

41. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Decarboxylation Reactions
 Removal of CO2 to produce AMINES
Histidine
41Biochemistry for medics- Namrata Chhabra

42. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Decarboxylation Reactions
 Removal of CO2 to produce AMINES
Decarboxylase
B6-P
CO2
Histidine
42Biochemistry for medics- Namrata Chhabra

43. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Decarboxylation Reactions
 Removal of CO2 to produce AMINES
Decarboxylase
B6-P
CO2
HistamineHistidine
43Biochemistry for medics- Namrata Chhabra

44. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Decarboxylation Reactions
 Removal of CO2 to produce AMINES
Decarboxylase
B6-P
CO2
HistamineHistidine
44Biochemistry for medics- Namrata Chhabra

45. Role in Amino Acid Metabolism
 General Amino Acid Reactions
Decarboxylation Reactions
 Removal of CO2 to produce AMINES
Histidine
5-OH Tryptophan
Glutamic Acid
Histamine
5-OH Tryptamine (Serotonin)
γ-Amino Butyric Acid
Decarboxylase
B6-P
CO2
Decarboxylase
B6-P
CO2
Decarboxylase
B6-P
CO2
45Biochemistry for medics- Namrata Chhabra

46.  Histamine
 Synthesised by Basophils and Mast Cells
 Mediator of Hypersensitivity Reactions
 Triggers Inflammatory Reactions
 Neurotransmitter in the Gut
 γ-Amino Butyric Acid
 Inhibitor Neurotransmitter in the CNS
 GABA Deficiency produces a state of Hyper excitation
 Convulsions
 Precipitating factor for Epileptic Seizures
 Serotonin
 Neurotransmitter in CNS
 Regulates Behaviour and Cognitive functions
 Deficiency leads to Depression, Anxiety and Personality Disorders
 Regulates Intestinal Motility in Gut
Role in Amino Acid Metabolism
CLINICAL SIGNIFICANCE
46Biochemistry for medics- Namrata Chhabra

47. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
47Biochemistry for medics- Namrata Chhabra

48. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 Niacin Deficiency
 PELLAGRA sets in
† Dermatitis
48Biochemistry for medics- Namrata Chhabra

49. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 Niacin Deficiency
 PELLAGRA sets in
† Dermatitis
49Biochemistry for medics- Namrata Chhabra

50. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 Niacin Deficiency
 PELLAGRA sets in
† Dermatitis
† Dementia
50Biochemistry for medics- Namrata Chhabra

51. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 Niacin Deficiency
 PELLAGRA sets in
† Dermatitis
† Dementia
† Diarrhoea
51Biochemistry for medics- Namrata Chhabra

52. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 Niacin Deficiency
 PELLAGRA sets in
† Dermatitis
† Dementia
† Diarrhoea
† DEATH
52Biochemistry for medics- Namrata Chhabra

53. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 Niacin Deficiency
 PELLAGRA sets in
† Dermatitis
† Dementia
† Diarrhoea
† DEATH
 In ISONIAZID therapy for Tuberculosis
Isoniazid
+
Isoniazid B6-P Hydrasone
B6-P
53Biochemistry for medics- Namrata Chhabra

54. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
NIACIN
Kynureninase
B6-P
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 Niacin Deficiency
 PELLAGRA sets in
† Dermatitis
† Dementia
† Diarrhoea
† DEATH
 In ISONIAZID therapy for Tuberculosis
Isoniazid
+
Isoniazid B6-P Hydrasone
B6-P
B6-P
54Biochemistry for medics- Namrata Chhabra

55. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
NIACIN
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 In ISONIAZID therapy for Tuberculosis
 Tryptophan Loading Test
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
55Biochemistry for medics- Namrata Chhabra

56. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
NIACIN
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 In ISONIAZID therapy for Tuberculosis
 Tryptophan Loading Test
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
Xanthurenic Acid
56Biochemistry for medics- Namrata Chhabra

57. Role in Amino Acid Metabolism
 Tryptophan Metabolism
Tryptophan
NIACIN
CLINICAL SIGNIFICANCE
 Pathway for Endogenous NIACIN synthesis
 In Vitamin B6 deficiency
 In ISONIAZID therapy for Tuberculosis
 Tryptophan Loading Test
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
Kynurenine
3-OH-Kynurenine
3-OH-Anthranilic Acid
Kynureninase
B6-P
Xanthurenic Acid
57Biochemistry for medics- Namrata Chhabra

58. Role in Amino Acid Metabolism
 Methionine Metabolism
 Methionine metabolism occurs in 2 phases
 Phase I - Conversion of Methionine to HOMOCYSTEINE
 Phase II - Further metabolism of HOMOCYSTEINE
Methionine
HOMOCYSTEINE Serine+
Cystathionine
CysteineHomoserine
Cystathionine β SynthaseB6-P
Cystathionine LyaseB6-P
CLINICAL SIGNIFICANCE
 Pathway for synthesis of Non-Essential
Amino Acids like Cysteine
 In Vitamin B6 deficiency
 HOMOCYSTEINAEMIA
 Homocysteine is Atherogenic
 Ischaemic Heart Disease
 Brain Stroke
58Biochemistry for medics- Namrata Chhabra

59. Role in Amino Acid Metabolism
 Glycine Metabolism
Glycine
HydroxyMethly THF
Interconversion of Glycine to Serine
59Biochemistry for medics- Namrata Chhabra

60. Serine Hydroxymethly
Transferase
B6-P
Glycine
Serine
“Free” THF
HydroxyMethly THF
Role in Amino Acid Metabolism
 Glycine Metabolism
Interconversion of Glycine to Serine
CLINICAL SIGNIFICANCE
 Synthesis of Non-Essential
Amino Acid Serine
60Biochemistry for medics- Namrata Chhabra

61. Serine Hydroxymethly
Transferase
B6-P
Glycine
Serine
“Free” THF
HydroxyMethly THF
Role in Amino Acid Metabolism
 Glycine Metabolism
Interconversion of Glycine to Serine
CLINICAL SIGNIFICANCE
 Synthesis of Non-Essential
Amino Acid Serine
61Biochemistry for medics- Namrata Chhabra

62. Tetra Hydro Folate
B6-P
GCS
Glycine
Role in Amino Acid Metabolism
 Glycine Metabolism
Glycine Cleavage System
62Biochemistry for medics- Namrata Chhabra

63. Tetra Hydro Folate
+
N5,10 Methylene Tetra Hydro Folate
B6-P
GCS
Glycine
Role in Amino Acid Metabolism
 Glycine Metabolism
Glycine Cleavage System
Carbon Dioxide Ammonia
63Biochemistry for medics- Namrata Chhabra

64. +
B6-P
GCS
Glycine
Role in Amino Acid Metabolism
 Glycine Metabolism
Glycine Cleavage System
CLINICAL SIGNIFICANCE
dUMP dTMP
Di Hydro Folate
DNA Synthesis
N5,10 Methylene Tetra Hydro Folate
Thymidylate Synthase
Carbon Dioxide Ammonia
64Biochemistry for medics- Namrata Chhabra

65. +
B6-P
GCS
Glycine
Role in Amino Acid Metabolism
 Glycine Metabolism
Glycine Cleavage System
CLINICAL SIGNIFICANCE
dUMP dTMP
Di Hydro Folate
DNA Synthesis
Thymidylate Synthase
Carbon Dioxide Ammonia
N5,10 Methylene Tetra Hydro Folate
65Biochemistry for medics- Namrata Chhabra

66. GlycineAcetyl CoA
+
Role in Amino Acid Metabolism
 Glycine Metabolism
Synthesis of Amino Acetone
66Biochemistry for medics- Namrata Chhabra

67. GlycineAcetyl CoA
Amino Acetone
Synthetase
B6-P
+
Role in Amino Acid Metabolism
 Glycine Metabolism
Synthesis of Amino Acetone
67Biochemistry for medics- Namrata Chhabra

68. Amino Acetone
GlycineAcetyl CoA
Amino Acetone
Synthetase
B6-P
+
Role in Amino Acid Metabolism
 Glycine Metabolism
Synthesis of Amino Acetone
CLINICAL SIGNIFICANCE
 Amino Acetone has a role in
Metabolism†
† Elliott, W.H., et al., 1959. Amino Acteone: Its
Isolation and Role in Metabolism, Canberra.
Nature: 183, 1051-1052.
68Biochemistry for medics- Namrata Chhabra

69.  Sources of Vitamin B6
 Structure of Vitamin B6
 Activation of Vitamin B6
 Role in Amino Acid Metabolism
 General Amino Acid Reactions
 Metabolism of Tryptophan
 Metabolism of Methionine
 Metabolism of Glycine
SUMMARY
69Biochemistry for medics- Namrata Chhabra

70.  Biehl, J.P., et al., 1954. Effect of Isoniazid on Vitamin B6 Metabolism; Its
Possible Significance in Producing Isoniazid Neuritis, London. Royal
Society of Medicine Press; 85:389-392.
 Robinson, K., et al., 1996. Hyperhomocysteinemia Confers an Independent
Increased Risk of Atherosclerosis in End-Stage Renal Disease and Is Closely
Linked to Plasma Folate and Pyridoxine Concentrations, Boston.
Circulation; 94:2743-2748
Bibliography
 Chatterjea, M.N., Shinde, R., 2008. Textbook of Medical Biochemistry, 7th
Edition, New Delhi. Jaypee.
 Murray, R.K., et al., 2009. Harper’s Illustrated Biochemistry, 28th Edition, New
York. McGraw Hill.
 Champe, C., et al., 2008. Lippincott’s Illustrated Review of Biochemistry, 4th
Edition , New York. Lippincott Williams and Wilkins.
 Chabba, N., 2011. Vitamin B6 chemistry, Activation and Role in Amino Acid
Metabolism. Biochemistry Lecture, Mauritius, SSR Medical College.
UNPUBLISHED.
70Biochemistry for medics- Namrata Chhabra

71. 71Biochemistry for medics- Namrata Chhabra