vitamin b12

1. V. N. Karazin Kharkiv National University
Vitamin B12
Presented by :- Mohammad Ezhaiman
Group: B.A.301

2. What is vitamin B-12?
 also called Cobalamin
 Water soluble vitamin
 Contribute in the normal functioning of the brain and nervous
system and for the hematopoiesis.
 coenzyme for enzymes that transfer methyl groups and produce red
blood cells.
 C63H88N14O14PCo

3. Vitamin B12 is composed of :

4. VitaminB12 Derivatives
• Cyanocobalamin (digested form)
• Hydroxycobalamin
• Chlorocobalamin
• Methylcobalamin
• Adenosylcobalamin
• (5’-deoxyadenosylcobalamin)

5. Sources of Vitamin B12 :-
 Natural forms
1. Produced by microorganisms (bacteria/fungi) may inhabit in gut
2. Plants do not produce or contain Vitamin B12
 Food sources rich in Vit.B12
1. Liver , Kidney , Muscle
2. Egg , Milk ,Cheese and other diary products
3. Seafood
4. Foods fortified with B12 are also sources of the vitamin B12.

6. Vitamin B12 Stores
 Normal body stores of vitamin B12 about 3-4 mg, primarily in liver.
 This would be sufficient for 3 years if dietary intake ceased or if the
ability to absorb the vitamin was lost.
Dietary requirement
 Recommended intake (RDA) 3μg/day
 6μg/day in pregnancy & Lactation

7. Absorption :-

8. B12 Reactions

11. Function :-
1. DNA synthesis
2. Fatty acid synthesis
3. Energy production. Amino Acids
4. Serine,
5. Methionine
6. Glycine,
7. Purine nucleotides
8. dTMP (Deoxy Thymidinne Mono Phosphate).

12. Vitamin B12 Deficiency :-
 Pernicious anemia arises when vitamin B12 deficiency impairs the
metabolism of folic acid, leading to functional folate deficiency that
disturbs erythropoiesis, causing immature precursors of erythrocytes
to be released into the circulation (megaloblastic anemia).
 The most common cause of pernicious anemia is failure of the
absorption of vitamin B12 rather than dietary deficiency. This can be
the result of failure of intrinsic factor secretion caused by
autoimmune disease affecting parietal cells.

13.  Symptoms:-
fatigue, depression, and poor memory may be experienced.
 Neurological complications :-
from a progressive demyelination of nerve cells due to increase in
methylmalonyl -CoA that result from vitamin B12 Deficiency .
Treatment:-
B12 supplement

14. Thank you very much

15. References :-
https://en.wikipedia.org/wiki/Vitamin_B12#Biochemistry
https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/
https://www.medicalnewstoday.com/articles/219822.php
https://www.aafp.org/afp/2011/0615/p1425.html