Editing Pemetrexed (section)

==Mechanism of action==
[[File:Pathway of tetrahydrofolate and antimetabolites.pdf|thumb|Pathway of tetrahydrofolate and antimetabolites]]
Pemetrexed is chemically similar to [[folic acid]] and is in the class of chemotherapy drugs called [[folate antimetabolite]]s.  It works by inhibiting three enzymes used in [[purine]] and [[pyrimidine]] synthesis—[[thymidylate synthase]] (TS), [[dihydrofolate reductase]] (DHFR), and [[glycinamide ribonucleotide formyltransferase]]<ref>{{cite journal | vauthors = McLeod HL, Cassidy J, Powrie RH, Priest DG, Zorbas MA, Synold TW, Shibata S, Spicer D, Bissett D, Pithavala YK, Collier MA, Paradiso LJ, Roberts JD | display-authors = 6 | title = Pharmacokinetic and pharmacodynamic evaluation of the glycinamide ribonucleotide formyltransferase inhibitor AG2034 | journal = Clinical Cancer Research | volume = 6 | issue = 7 | pages = 2677–2684 | date = July 2000 | pmid = 10914709 | url = http://clincancerres.aacrjournals.org/cgi/content/abstract/6/7/2677 | access-date = 2 December 2008 | url-status = live | archive-url = https://web.archive.org/web/20090728001330/http://clincancerres.aacrjournals.org/cgi/content/abstract/6/7/2677 | archive-date = 28 July 2009 }}</ref><ref>{{cite book | vauthors = Avendano C, Menendez JC | title = Medicinal Chemistry of Anticancer Drugs | publisher = [[Elsevier]] | date = April 2008 | location = Amsterdam | page = 37 | url = https://books.google.com/books?id=GjhXyqB5iLcC | isbn = 978-0-444-52824-7 }}</ref> (GARFT). By inhibiting the formation of precursor purine and pyrimidine [[nucleotide]]s, pemetrexed prevents the formation of [[DNA]] and [[RNA]], which are required for the growth and survival of both normal cells and cancer cells.