Editing Enzyme (section)

====Competitive====
A [[competitive inhibitor]] and substrate cannot bind to the enzyme at the same time.<ref name = "Price_1979">{{cite journal | vauthors = Price NC | year = 1979 | title = What is meant by 'competitive inhibition'? | journal = Trends in Biochemical Sciences | volume = 4 | issue=11 | pages = N272–N273 | doi = 10.1016/0968-0004(79)90205-6 }}</ref> Often competitive inhibitors strongly resemble the real substrate of the enzyme. For example, the drug [[methotrexate]] is a competitive inhibitor of the enzyme [[dihydrofolate reductase]], which catalyzes the reduction of [[folic acid|dihydrofolate]] to tetrahydrofolate.<ref name="Goodsell 340–341">{{cite journal | vauthors = Goodsell DS | title = The molecular perspective: methotrexate | journal = The Oncologist | volume = 4 | issue = 4 | pages = 340–341 | date = 1999-08-01 | pmid = 10476546 | doi = 10.1634/theoncologist.4-4-340 | doi-access = free }}</ref> The similarity between the structures of dihydrofolate and this drug are shown in the accompanying figure. This type of inhibition can be overcome with high substrate concentration. In some cases, the inhibitor can bind to a site other than the binding-site of the usual substrate and exert an [[#Allosteric modulation|allosteric effect]] to change the shape of the usual binding-site.<ref>{{cite journal | vauthors = Wu P, Clausen MH, Nielsen TE | title = Allosteric small-molecule kinase inhibitors | journal = Pharmacology & Therapeutics | volume = 156 | pages = 59–68 | date = December 2015 | pmid = 26478442 | doi = 10.1016/j.pharmthera.2015.10.002 | s2cid = 1550698 | url = https://backend.orbit.dtu.dk/ws/files/129911346/PT_Revised_Main_Manuscript_with_embedded_figures.pdf }}</ref>