{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T21:13:32Z","timestamp":1789506812017,"version":"build-2803163510"},"reference-count":39,"publisher":"National Academy of Sciences","issue":"47","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2007,11,20]]},"abstract":"<jats:p>\n                    The uncatalyzed reactions of O\n                    <jats:sub>2<\/jats:sub>\n                    (S = 1) with organic substrates (S = 0) are thermodynamically favorable but kinetically slow because they are spin-forbidden and the one-electron reduction potential of O\n                    <jats:sub>2<\/jats:sub>\n                    is unfavorable. In nature, many of these important O\n                    <jats:sub>2<\/jats:sub>\n                    reactions are catalyzed by metalloenzymes. In the case of mononuclear non-heme iron enzymes, either Fe\n                    <jats:sup>II<\/jats:sup>\n                    or Fe\n                    <jats:sup>III<\/jats:sup>\n                    can play the catalytic role in these spin-forbidden reactions. Whereas the ferrous enzymes activate O\n                    <jats:sub>2<\/jats:sub>\n                    directly for reaction, the ferric enzymes activate the substrate for O\n                    <jats:sub>2<\/jats:sub>\n                    attack. The enzyme\u2013substrate complex of the ferric intradiol dioxygenases exhibits a low-energy catecholate to Fe\n                    <jats:sup>III<\/jats:sup>\n                    charge transfer transition that provides a mechanism by which both the Fe center and the catecholic substrate are activated for the reaction with O\n                    <jats:sub>2<\/jats:sub>\n                    . In this Perspective, we evaluate how the coupling between this experimentally observed charge transfer and the change in geometry and ligand field of the oxidized metal center along the reaction coordinate can overcome the spin-forbidden nature of the O\n                    <jats:sub>2<\/jats:sub>\n                    reaction.\n                  <\/jats:p>","DOI":"10.1073\/pnas.0704191104","type":"journal-article","created":{"date-parts":[[2007,11,14]],"date-time":"2007-11-14T21:19:01Z","timestamp":1195075141000},"page":"18355-18362","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":105,"title":["Substrate activation for O\n                    <sub>2<\/sub>\n                    reactions by oxidized metal centers in biology"],"prefix":"10.1073","volume":"104","author":[{"given":"Monita Y. M.","family":"Pau","sequence":"first","affiliation":[{"name":"Department of Chemistry, Stanford University, Stanford, CA 94305-5080; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John D.","family":"Lipscomb","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, Molecular Biology and Biophysics and the Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edward I.","family":"Solomon","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Stanford University, Stanford, CA 94305-5080; and"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[2007,11,20]]},"reference":[{"key":"e_1_3_4_1_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr00027a011"},{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1432-1033.1997.t01-1-00625.x"},{"key":"e_1_3_4_3_2","first-page":"243","volume":"28","author":"Lipscomb JD","year":"1992","unstructured":"JD Lipscomb, AM Orville Metal Ions Biol Syst 28, 243\u2013298 (1992).","journal-title":"Metal Ions Biol Syst"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr960039f"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr9900275"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/0005-2760(91)90063-N"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.pp.42.060191.001045"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/0005-2760(92)90297-9"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.bi.63.070194.002123"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4615-4861-4_2"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.8502991"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi960576u"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi002893d"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.1016\/0959-440X(94)90270-4"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1074-5521(97)90113-7"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja982844c"},{"key":"e_1_3_4_17_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.7569922"},{"key":"e_1_3_4_18_2","doi-asserted-by":"publisher","DOI":"10.1039\/a815513y"},{"key":"e_1_3_4_19_2","doi-asserted-by":"publisher","DOI":"10.1039\/b100484k"},{"key":"e_1_3_4_20_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi00500a019"},{"key":"e_1_3_4_21_2","doi-asserted-by":"publisher","DOI":"10.1006\/jmbi.1994.1754"},{"key":"e_1_3_4_22_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja011945z"},{"key":"e_1_3_4_23_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi970469f"},{"key":"e_1_3_4_24_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja053800o"},{"key":"e_1_3_4_25_2","doi-asserted-by":"publisher","DOI":"10.1016\/0005-2744(76)90182-0"},{"key":"e_1_3_4_26_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0021-9258(17)43071-7"},{"key":"e_1_3_4_27_2","doi-asserted-by":"publisher","DOI":"10.1016\/0005-2744(77)90193-0"},{"key":"e_1_3_4_28_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00232a021"},{"key":"e_1_3_4_29_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja00024a028"},{"key":"e_1_3_4_30_2","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1021\/bk-1998-0692.ch023","volume-title":"Spectroscopic Methods in Bioinorganic Chemistry","author":"Lipscomb JD","year":"1998","unstructured":"JD Lipscomb, AM Orville, RW Frazee, KB Dolbeare, N Elango, DH Ohlendorf Spectroscopic Methods in Bioinorganic Chemistry, eds EI Solomon, KO Hodgson (Am Chem Soc, Washington, DC), pp. 387\u2013402 (1998)."},{"key":"e_1_3_4_31_2","doi-asserted-by":"publisher","DOI":"10.1246\/cl.1987.719"},{"key":"e_1_3_4_32_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1381-1169(99)00198-3"},{"key":"e_1_3_4_33_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jinorgbio.2004.12.004"},{"key":"e_1_3_4_34_2","first-page":"591","volume":"9","author":"Kim M","year":"2002","unstructured":"M Kim, T Okajima, S Kishishita, M Yoshimura, A Kawamori, K Tanizawa, H Yamaguchi Nat Struct Biol 9, 591\u2013596 (2002).","journal-title":"Nat Struct Biol"},{"key":"e_1_3_4_35_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi992225w"},{"key":"e_1_3_4_36_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja065671x"},{"key":"e_1_3_4_37_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja0641251"},{"key":"e_1_3_4_38_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi970468n"},{"key":"e_1_3_4_39_2","doi-asserted-by":"publisher","DOI":"10.1021\/bi972047b"}],"updated-by":[{"DOI":"10.1073\/pnas.0711661105","type":"correction","label":"Correction","source":"publisher","updated":{"date-parts":[[2008,1,22]],"date-time":"2008-01-22T00:00:00Z","timestamp":1200960000000}}],"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.0704191104","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,12]],"date-time":"2022-04-12T16:39:39Z","timestamp":1649781579000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.0704191104"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007,11,20]]},"references-count":39,"journal-issue":{"issue":"47","published-print":{"date-parts":[[2007,11,20]]}},"alternative-id":["10.1073\/pnas.0704191104"],"URL":"https:\/\/doi.org\/10.1073\/pnas.0704191104","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007,11,20]]},"assertion":[{"value":"2007-06-22","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2007-11-20","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}