{{Short description|Molecular biology technique}} '''Photoaffinity labeling''' is a chemoproteomics technique used to attach "labels" to the active site of a large molecule, especially a protein. The "label" attaches to the molecule loosely and reversibly, and has an inactive site which can be converted using photolysis into a highly reactive form, which causes the label to bind more permanently to the large molecule via a covalent bond.<ref>[https://www.merriam-webster.com/medical/photoaffinity%20labeling Photoaffinity labeling]</ref><ref>[https://goldbook.iupac.org/P04578.html Photoaffinity labeling], Gold Book</ref> The technique was first described in the 1970s.<ref>{{Cite journal | doi = 10.1073/pnas.70.9.2567 | last1 = Ruoho | first1 = A. E. | last2 = Kiefer | first2 = H. | last3 = Roeder | first3 = P. E. | last4 = Singer | first4 = S. J. | title = The mechanism of photoaffinity labeling | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 70 | issue = 9 | pages = 2567–2571 | year = 1973 | pmid = 4517671 | pmc = 427057 | bibcode = 1973PNAS...70.2567R | doi-access = free }}</ref> Molecules that have been used as labels in this process are often analogs of complex molecules, in which certain functional groups are replaced with a photoreactive group, such as an azide, a diazirine or a benzophenone.<ref>{{Cite journal | last1 = Bush | first1 = J. T. | last2 = Walport | first2 = L. J. | last3 = McGouran | first3 = J. F. | last4 = Leung | first4 = I. K. H. | last5 = Berridge | first5 = G. | title = The Ugi four-component reaction enables expedient synthesis and comparison of photoaffinity probes | doi = 10.1039/C3SC51708J | journal = Chemical Science | volume = 4 | issue = 12 | pages = 4115–4120 | year = 2013 | pmid = | pmc = | doi-access = free}}</ref><ref>{{Cite journal | last1 = Panov | first1 = M. S. | last2 = Voskresenska | first2 = V. D. | last3 = Ryazantsev | first3 = M. N. | last4 = Tarnovsky | first4 = A. N. | last5 = Wilson | first5 = R. M. | title = 5-Azido-2-aminopyridine, a New Nitrene/Nitrenium Ion Photoaffinity Labeling Agent That Exhibits Reversible Intersystem Crossing between Singlet and Triplet Nitrenes | doi = 10.1021/ja405637b | journal = Journal of the American Chemical Society | volume = 135 | issue = 51 | pages = 19167–19179 | year = 2013 | pmid = 24219134 | pmc = | bibcode = 2013JAChS.13519167P | url = https://scholarworks.bgsu.edu/chem_pub/182 | url-access = subscription }}</ref><ref>{{Cite journal | last1 = Akiyama | first1 = S. | last2 = Cornwell | first2 = M. M. | last3 = Kuwano | first3 = M. | last4 = Pastan | first4 = I. | last5 = Gottesman | first5 = M. M. | title = Most drugs that reverse multidrug resistance also inhibit photoaffinity labeling of P-glycoprotein by a vinblastine analog | journal = Molecular Pharmacology | volume = 33 | issue = 2 | pages = 144–147 | year = 1988 | pmid = 2893251 }}</ref>
==References== {{Reflist}}
Category:Molecular biology techniques