https://wiki.tiffa.net/w/index.php?action=history&feed=atom&title=Translations%3AVitamin_B12%2F73%2FenTranslations:Vitamin B12/73/en - Revision history2026-05-28T06:27:30ZRevision history for this page on the wikiMediaWiki 1.43.0https://wiki.tiffa.net/w/index.php?title=Translations:Vitamin_B12/73/en&diff=135267&oldid=prevFuzzyBot: Importing a new version from external source2024-04-05T11:15:36Z<p>Importing a new version from external source</p>
<p><b>New page</b></p><div>==Synthesis==<br />
===Biosynthesis===<br />
{{Main|Cobalamin biosynthesis}}<br />
Vitamin B<sub>12</sub> is derived from a [[tetrapyrrole|tetrapyrrolic structural framework]] created by the enzymes [[Porphobilinogen deaminase|deaminase]] and [[uroporphyrinogen III synthase|cosynthetase]] which transform [[aminolevulinic acid]] via [[porphobilinogen]] and [[hydroxymethylbilane]] to [[uroporphyrinogen III]]. The latter is the first [[macrocycle|macrocyclic]] intermediate common to [[heme]], [[chlorophyll]], [[siroheme]] and B<sub>12</sub> itself. Later steps, especially the incorporation of the additional methyl groups of its structure, were investigated using <sup>13</sup>C [[isotopic labelling|methyl-labelled]] [[S-adenosyl methionine]]. It was not until a [[genetic engineering|genetically engineered]] strain of ''[[Pseudomonas denitrificans]]'' was used, in which eight of the genes involved in the biosynthesis of the vitamin had been [[gene expression|overexpressed]], that the complete sequence of [[methylation]] and other steps could be determined, thus fully establishing all the intermediates in the pathway.</div>FuzzyBot