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Vitamin B Biochemistry

Truth is we’ve been delaying this article for a while until we had enough information & facts to allow us to enlighten our readers. Hopefully by the end of this article you’ll have no doubts about this subject.

Statpearls [Internet].

There are two main groups of vitamins – fat-soluble (easily stored in fat upon absorption) and water-soluble (washed out and not easily stored). Although adequate intake of all vitamins is important, regular intake is required to avoid deficiency due to the transient nature of water-soluble vitamins. The water-soluble vitamins include Vitamin C and Vitamin B complex (thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate, and cobalamin).

Introduction

The water-soluble vitamins include Vitamin C and Vitamin B complex (thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, biotin, folate, and cobalamin). In addition to serving as cofactors in biochemical reactions, the vitamin B complex is vital for normal body growth and development, healthy skin, the proper function of nerves and the heart, and red blood cell formation.

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Related Terms:

Amin B 12 )

Vitamin B 12 has a complex ring structure (tetrapyrrole) and an atom of cobalt in the center as shown in Fig.
Vitamin B 12 is synthesized by microorganisms. The cobalamin-intrinsic factor complex is absorbed in the ileum after attaching to cubilin, a receptor for the cobalamin-intrinsic factor complex. Cubilin facilitates the absorption of the complex.
Mutation of the gene for cubilin results in impaired absorption of the cobalamin-intrinsic factor complex generating the rare megaloblastic anemia (formation of red blood cells requires vitamin B 12 , folic acid and iron; a deficiency in any one of these, causes anemia). Normally, vitamin B 12 is bound to the transporting protein, transcobalamin II, in the intestinal cells, and the vitamin B 12 -transcobalamin II complex is carried in the bloodstream to tissue cells and to the liver where it is stored as a complex of vitamin B 12 -transcobalamin III (transcobalamin III is also present in blood). In the liver, the stored form of vitamin B 12 can be released into the small intestine through the bile; then vitamin B 12 is released from the complex, becomes bound to intrinsic factor and cycles again through the intrinsic factor-vitamin B 12 -cubilin complex, and eventually reaches the bloodstream bound to the transporting protein.
The 5′-deoxyadenosine derivative (Fig. Structure of the 5′-deoxyadenosine derivative of cobalamin. This form of cobalamin is involved in methionine synthase that catalyzes the conversion of homocysteine to methionine.
In this reaction, a methyl group is transferred from N5-methyltetrahydrofolate to hydroxycobalamin. When cobalamin is deficient because the intrinsic factor is absent or inactive, folic acid becomes trapped as the N5-methyltetrahydrofolate due to the inactivity of methionine synthase. Additionally, there is an increase in methylmalonyl-CoA resulting in the inhibition of fatty acid synthesis essential for the turnover of the myelin sheath (of neurons), and this results in progressive demyelinatio.

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Citation, Doi And Article Data

However the chemical structures of these compounds are structurally heterogeneous and they do not constitute a distinct biochemical group. They are all water soluble vitamins. Some of the B vitamins are known by their number, e.g.
Biotin, which is actually vitamin B 7 , although few realize this.

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