Explain the functions of folate, Biology

Assignment Help:

Explain the Functions of Folate?

Folate, also known as folic acid, is essential for good health. Folate requiring reactions include those involved in phases of amino acid metabolism, DNA (purine and pyrimidine) biosynthesis and the formation of the primary methylating agent, S-adenosyl methionine (SAM) as shown in Figure. Folate is involved in the de novo synthesis of purines (adenine and guanine), requiring the folate form, 10-formyl tetrahydro folic acid (THF), which is produced from 5, 10-methylene THF reactions catalyzed by the enzyme THF synthetase. The 510- methylene THF molecule has several fates, one of which is the reconversion to 5- methyl THF, catalyzed by methylene tetra hydrofolate reductase (MTHFR). Thus, folate in its reduced and polyglutamylated forms is essential for the DNA biosynthesis cycle, as shown in Figure. This conversion (5, 10-methylene THF molecule reconversion to 5-methyl THF) forms methionine from homocysteine. Folate, specially helps in reducing the risk of heart disease and stroke by lowering the level of the amino acid homocysteine in the blood (by forming methionine). At high levels, homocysteine can damage coronary arteries or make it easier for blood clotting cells to clump together and form a clot. This can increase the risk of heart attack or stroke. This methylation reaction (refer to Figure) requires the enzyme methionine synthase, cobalamin (vitamin BIZ) and 5-methyl THF. A methyl group is removed from 5 methyl THF and is sequentially transferred first to cobalamin coenzyme and then to homocysteine forming methionine and reconverting 5-methyl THF to tetrahydrofolate (THF). The dependency of methionine synthase on both folate and cobalamin explains why a single deficiency of either vitamin leads to the same megaloblastic changes in the bone marrow and other tissues, with rapidly dividing cells.
 
 Alternatively 5, 10-methylenetetrahydrofolate can be channelled to the methylation cycle (refer to Figure). This cycle has two functions. It ensures that the cell always has an adequate supply of S-adenosylmethionine (SAM), an activated form of methionine which acts as a methyl donor to a wide range of methyltransferases. The methyltransferases methylate a wide range of substrates including lipids, hormones, DNA and proteins. One particularly important methylation is that of myelin basic protein, which acts as insulation for nerve cells. When the methylation cycle is interrupted, as it is during vitamin BIZ deficiency, one of the clinical consequences is the demyelination of nerve cells resulting in a neuropathy which leads to ataxia (lack of coordination), paralysis, and, if untreated, ultimately death. Other important methyltransferase enzymes down-regulate DNA and suppress cell division.


Related Discussions:- Explain the functions of folate

Protective role and metal chelating ability - nicotinic acid, Define Protec...

Define Protective role and Metal chelating ability? Protective role: Nicotinic acid is vital to the normal functioning of the skin intestinal tract and nervous system. It p

Dentition and feeding, briefly explain filter feeding in holozoicanimals

briefly explain filter feeding in holozoicanimals

Chest examination of new born, Chest Observe for retraction of the...

Chest Observe for retraction of the intercostal muscle which is indicative of severe respiratory distress (a sign of hyaline membrane  disease).  Inspect the brea

What concerns should alek''s healthcare, Nine-year-old Alek is admitted to ...

Nine-year-old Alek is admitted to the emergency room with a closed fracture of the right femur. Radiography revels that the fracture crosses the distal epiphyseal plate. What conce

Explain pasteurization, Explain Pasteurization The act or process of h...

Explain Pasteurization The act or process of heating a beverage or other food, to a specific temperature for a specific period of time in order to kill microorganisms that cou

Describe g-protein, Which of the following is true for a G-protein? A. ...

Which of the following is true for a G-protein? A. When an agonist binds to the binding site of a G-protein-coupled receptor (GPCR), this leads to GDP displacing a GTP bound to

Illustrate fundamental sexual life cycles, Q. What are the three fundamenta...

Q. What are the three fundamental sexual life cycles studied in Biology? Which of them corresponds to metagenesis? Which of them is the human life cycle? Sexual reproduction ma

Deficiency diseases-iron deficiency, Iron deficiency Iron plays an ess...

Iron deficiency Iron plays an essential role in oxygen transport in the body as a constituent of haemoglobin where nearly 60% of the body iron is found. Apart from oxygen tran

What is the significance of water for enzymatic activity, Q. What is the si...

Q. What is the significance of water for enzymatic activity? Enzymes, Biological catalysts, depend on water to reach their substrates and bind to them. There is no enzymatic ac

What ways farmers try to improve the quality of their soil, a) In what way...

a) In what ways do farmers try to improve the quality of (i) their soil, (ii) their crop plants?    b) What other steps do farmers take to maximise the yield from their

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd