Editing Histidine (section)

=== Conversion to other biologically active amines ===
* The histidine amino acid is a precursor for [[histamine]], an amine produced in the body necessary for inflammation.<ref>{{Cite journal|last1=Andersen|first1=Hjalte H.|last2=Elberling|first2=Jesper|author-link3=Lars Arendt-Nielsen|last3=Arendt-Nielsen|first3=Lars|date=2015-09-01|title=Human surrogate models of histaminergic and non-histaminergic itch|journal=Acta Dermato-Venereologica|volume=95|issue=7|pages=771–777|doi=10.2340/00015555-2146|issn=1651-2057|pmid=26015312|url=http://vbn.aau.dk/files/219083590/4442_9.pdf|doi-access=free}}</ref> 
* The enzyme [[histidine ammonia-lyase]] converts histidine into [[ammonia]] and [[urocanic acid]]. A deficiency in this enzyme is present in the rare metabolic disorder [[histidinemia]], producing [[urocanic aciduria]] as a key diagnostic finding.
* Histidine can be converted to [[3-methylhistidine]], which serves as a [[biomarker (medicine)|biomarker]] for skeletal muscle damage, by certain [[methyltransferase]] enzymes.<ref name="HMDB 3-Methylhistidine">{{cite web | title=3-Methylhistidine | url=http://www.hmdb.ca/metabolites/HMDB00479 | work=HMDB Version&nbsp;4.0 | publisher=Human Metabolome Database | access-date=25 December 2017 | date=20 December 2017 }}</ref> 
* Histidine is also a precursor for [[carnosine]] [[biosynthesis]], which is a dipeptide found in skeletal muscle.<ref>{{Cite journal|last1=Derave|first1=Wim|last2=Everaert|first2=Inge|last3=Beeckman|first3=Sam|last4=Baguet|first4=Audrey|date=2010-03-01|title=Muscle carnosine metabolism and beta-alanine supplementation in relation to exercise and training|journal=Sports Medicine|volume=40|issue=3|pages=247–263|doi=10.2165/11530310-000000000-00000|issn=1179-2035|pmid=20199122|hdl=1854/LU-897781|s2cid=7661250|url=https://biblio.ugent.be/publication/897781|hdl-access=free}}</ref>
* In [[Actinomycetota]] and filamentous fungi, such as ''[[Neurospora crassa]]'', histidine can be converted into the [[antioxidant]] [[ergothioneine]].<ref name="Fahey">{{cite journal |doi=10.1146/annurev.micro.55.1.333 |title=Novelthiols Ofprokaryotes |year=2001 |last1=Fahey |first1=Robert C. |journal=Annual Review of Microbiology |volume=55 |pages=333–56 |pmid=11544359}}</ref>
[[File:Histidine decarboxylase.svg|thumb|center|400px|Conversion of histidine to [[histamine]] by [[histidine decarboxylase]]]]