Editing Biotin (section)

==Biosynthesis==
Biotin, synthesized in plants, is essential to plant growth and development.<ref name=Maruyama>{{cite journal |vauthors=Maruyama J, Yamaoka S, Matsuo I, Tsutsumi N, Kitamoto K |title=A newly discovered function of peroxisomes: involvement in biotin biosynthesis |journal=Plant Signal Behav |volume=7 |issue=12 |pages=1589–93 |date=December 2012 |pmid=23073000 |pmc=3578898 |doi=10.4161/psb.22405 |url=}}</ref> Bacteria also synthesize biotin,<ref name=Satiputra2016>{{cite journal |vauthors=Satiaputra J, Shearwin KE, Booker GW, Polyak SW |title=Mechanisms of biotin-regulated gene expression in microbes |journal=Synth Syst Biotechnol |volume=1 |issue=1 |pages=17–24 |date=March 2016 |pmid=29062923 |pmc=5640590 |doi=10.1016/j.synbio.2016.01.005 |url=}}</ref> and it is thought that bacteria resident in the large intestine may synthesize biotin that is absorbed and utilized by the host organism.<ref name=Said2013 />

Biosynthesis starts from two precursors, [[alanine]] and [[pimelic acid|pimeloyl]]-CoA. These form 7-keto-8-aminopelargonic acid (KAPA). KAPA is transported from plant peroxisomes to mitochondria where it is converted to 7,8-diaminopelargonic acid (DAPA) with the help of the enzyme, BioA. The enzyme dethiobiotin synthetase catalyzes the formation of the ureido ring via a DAPA carbamate activated with ATP, creating dethiobiotin with the help of the enzyme, BioD, which is then converted into biotin which is catalyzed by BioB.<ref name="Cronan, J. E 2020">{{cite journal |last1=Hu |first1=Yuanyuan |last2=Cronan |first2=John E. |date=2020-11-05 |title=α-proteobacteria synthesize biotin precursor pimeloyl-ACP using BioZ 3-ketoacyl-ACP synthase and lysine catabolism |journal=Nature Communications |language=en |volume=11 |issue=1 |pages=5598 |doi=10.1038/s41467-020-19251-5 |issn=2041-1723 |pmc=7645780 |pmid=33154364|bibcode=2020NatCo..11.5598H }}</ref> The last step is catalyzed by [[biotin synthase]], a radical SAM enzyme.  The sulfur is donated by an unusual [2Fe-2S] ferredoxin.<ref>{{cite book| doi = 10.1016/bs.mie.2018.06.003|chapter = Purification, Characterization, and Biochemical Assays of Biotin Synthase from ''Escherichia coli''|title = Radical SAM Enzymes|series = Methods in Enzymology|year = 2018|last1 = Cramer|first1 = Julia D.|last2 = Jarrett|first2 = Joseph T.|volume = 606|pages = 363–388|pmid = 30097099|isbn = 9780128127940}}</ref> Depending on the species of bacteria, Biotin can be synthesized via multiple pathways.<ref name="Cronan, J. E 2020" />