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Discovery of Vitamin B12

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July 6, 2020
Karl Folkers

In 1926, Harvard physicians discovered that eating half a pound of liver daily would prevent Pernicious Anemia. The hunt was on to identify the compound in liver that was responsible. In 1947, Karl Folkers (a scientist at Merck) isolated the tiny red crystals of vitamin B12. 'Extrinsic Factor' now had a name.

Extrinsic Factor

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July 3, 2020

It was first noticed in 1929 that giving beef alone to Pernicious Anemia patients did not improve the anemia, but when given with human gastric juice, it did. Giving gastric juice alone (without beef) didn't help either. In 1936, the scientist, W.B Castle called the substance in beef 'Extrinsic Factor' and the substance in gastric juice 'Intrinsic Factor'. They only work when given together. Today we know Extrinsic Factor by a different name, vitamin B12.

Gene Methylation

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June 30, 2020

Gene expression can be regulated without changing the DNA sequence through what is called an 'epigenetic mechanism' that frequently involves 'methylation'. The attachment of a methyl group (-CH3) to one of the DNA building blocks (cytosine) stops the gene being read. These methyl groups come from choline, betaine, folate and vitamin B12.

Pernicious Anemia

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June 29, 2020

The word 'pernicious'  means 'a harmful effect, especially in a gradual way'. This is the name given to an anemia characterized by larger, more immature red blood cells that is caused by vitamin B12 deficiency. It takes a long time to develop because it can take years to deplete the body stores of this vitamin in the liver.

What is a Cell Receptor?

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June 26, 2020

The integrity of the cell is protected by a membrane barrier that is selective for what it allows in or keeps out. Embedded in the cell membrane are specialized proteins that recognize very specific molecules to transport into or out of the cell. Vitamin B12 is absorbed through one of these specialized receptors.

Vitamin B12 is Vulnerable

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June 25, 2020

B12 is the largest and most complex vitamin and that makes it vulnerable to be damaged by digestive enzymes. Two proteins are specially designed to protect B12 in the GI tract. Haptocorrin protects B12 in the stomach and Intrinsic Factor (IF) protects it on its long journey down the small intestine to the B12 receptors for absorption.

Red Blood and B12

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June 24, 2020

Hemoglobin in red blood cells has 4 heme molecules, each comprising a large ring structure called a porphyrin, at the center of which is iron (Fe) that binds oxygen. B12 also has a porphyrin structure that contains cobalt (Co) at the center. Both heme and B12 absorb blue and green light and reflects red light, giving them their bright red color.

The B Team

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June 21, 2020

The Vitamin B Team. B12 (cobalamin) B9 (Folate) B6 (pyridoxine) and choline are interconnected in what is called 'transmethylation metabolism'. Foods containing these essential nutrients make 'methyl groups' or single carbon units (-CH3) available for use in the methionine pathway - critical to DNA expression.

Naming B12

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June 19, 2020

Vitamin B12 is the collective term for a group compounds known as cobalamin (because they contain the mineral cobalt). The two main forms of cobalamin are cyanocobalamin and hydroxycobalamin and there are two 'co-enzyme' forms called methylcobalamin and adenosylcobalamin. There is a good reason for why there are different forms of B12.

Natural Synthetic B12

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June 17, 2020

Chemical synthesis of B12 is tedious and requires about 70 reactions. Microbes like bacteria can produce B12 more efficiently from scratch, or by using fragments via a 'salvage' pathway (analogous to assembling a car from junkyard parts). B12 manufacturers produce the world's supply in massive fermentation tanks containing B12 producing bacteria and only a handful are capable of doing so at large scale in these microbial bioreactors

B12 is BIG

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June 16, 2020

B12 is 3 times bigger than the next biggest vitamin (vit K) and 11 times bigger than the smallest (nicotinic acid or B3). It took an international collaboration of 19 countries, 103 scientists (from Harvard and the Swiss Institute of Technology) 12 years to synthesize it in 62 chemical steps. It is the most complex vitamin by far - it must be important.