Editing Small molecule (section)

== Research tools ==
[[Image:Regen2.svg|thumb|200px|Cell culture example of a small molecule as a tool instead of a protein. In [[cell culture]] to obtain a [[Islets of Langerhans|pancreatic lineage]] from [[mesoderm]]al [[stem cells]], the [[retinoic acid]] signaling pathway must be activated while the [[sonic hedgehog]] pathway inhibited, which can be done by adding to the [[Growth medium|media]] anti-shh [[antibodies]], [[HHIP|Hedgehog interacting protein]], or [[cyclopamine]], where the first two molecules are proteins and the last a small molecule.<ref name="pmid17272496">{{cite journal |vauthors=Mfopou JK, De Groote V, Xu X, Heimberg H, Bouwens L | title = Sonic hedgehog and other soluble factors from differentiating embryoid bodies inhibit pancreas development | journal = Stem Cells | volume = 25 | issue = 5 | pages = 1156–65 |date=May 2007 | pmid = 17272496 | doi = 10.1634/stemcells.2006-0720 | s2cid = 32726998 | doi-access = free }}</ref>]] Enzymes and receptors are often activated or inhibited by [[Ligand (biochemistry)|endogenous protein]], but can be also inhibited by endogenous or exogenous [[Enzyme inhibitor|small molecule inhibitors]] or [[Enzyme inhibitor|activators]], which can bind to the [[active site]] or on the [[Allosteric regulation|allosteric site]].

An example is the teratogen and carcinogen [[phorbol 12-myristate 13-acetate]], which is a plant terpene that activates [[protein kinase C]], which promotes cancer, making it a useful investigative tool.<ref name="isbn0-471-58651-X">{{cite book | vauthors = Voet JG, Voet D | title = Biochemistry | publisher = J. Wiley & Sons | location = New York | year = 1995 | isbn = 978-0-471-58651-7 | url-access = registration | url = https://archive.org/details/biochemistry00voet_0 }}</ref> There is also interest in creating small molecule [[artificial transcription factors]] to regulate [[gene expression]], examples include wrenchnolol (a wrench shaped molecule).<ref name="pmid17894442">{{cite journal |vauthors=Koh JT, Zheng J | title = The new biomimetic chemistry: artificial transcription factors | journal = ACS Chem. Biol. | volume = 2 | issue = 9 | pages = 599–601 |date=September 2007 | pmid = 17894442 | doi = 10.1021/cb700183s | doi-access = free }}</ref>

Binding of [[Ligand (biochemistry)|ligand]] can be characterised using a variety of analytical techniques such as [[surface plasmon resonance]], [[microscale thermophoresis]]<ref name="pmid20981028">{{cite journal |vauthors=Wienken CJ, Baaske P, Rothbauer U, Braun D, Duhr S | title = Protein-binding assays in biological liquids using microscale thermophoresis | journal = Nat Commun | volume = 1 | issue = 7| pages = 100 | year = 2010 | pmid = 20981028 | doi = 10.1038/ncomms1093 | bibcode = 2010NatCo...1..100W | doi-access = free }}</ref> or [[dual polarisation interferometry]] to quantify the reaction affinities and kinetic properties and also any induced [[conformational change]]s.