{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T15:31:17Z","timestamp":1774279877028,"version":"3.50.1"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"2","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1980,11,1]]},"abstract":"<jats:p>A detailed study is presented of the room-temperature absorption, natural and magnetic circulation-dichroism (c.d. and m.c.d.) spectra of cytochrome c oxidase and a number of its derivatives in the wavelength range 700-1900 nm. The spectra of the reduced enzyme show a strong negative c.d. band peaking at 1100nm arising from low-spin ferrous haem a and a positive m.c.d. peak at 780nm assigned to high-spin ferrous haem a3. Addition of cyanide ion doubles the intensity of the low-spin ferrous haem c.d. band and abolishes reduced carbonmonoxy derivative the haem a32+-CO group shows no c.d. or m.c.d. bands at wavelengths longer than 700nm. A comparison of the m.c.d. spectra of the oxidized and cyanide-bound oxidized forms enables bands characteristic of the high-spin ferric form of haem a33+ to be identified between 700 and 1300nm. At wavelengths longer than 1300nm a broad positive m.c.d. spectrum, peaking at 1600nm, is observed. By comparison with the m.c.d. spectrum of an extracted haem a-bis-imidazole complex this m.c.d. peak is assigned to one low-spin ferric haem, namely haem a3+. On binding of cyanide to the oxidized form of the enzyme a new, weak, m.c.d. signal appears, which is assigned to the low-spin ferric haem a33+-CN species. A reductive titration, with sodium dithionite, of the cyanide-bound form of the enzyme leads to a partially reduced state in which low-spin haem a2+ is detected by means of an intense negative c.d. peak at 1100 nm and low-spin ferric haem a33+-CN gives a sharp positive m.c.d. peak at 1550nm. The c.d. and m.c.d. characteristics of the 830nm absorption band in oxidized cytochrome c oxidase are not typical of type 1 blue cupric centres.<\/jats:p>","DOI":"10.1042\/bj1910319","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T20:24:57Z","timestamp":1439238297000},"page":"319-331","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":41,"title":["Near-infrared magnetic and natural circular dichroism of cytochrome <i>c<\/i> oxidase"],"prefix":"10.1042","volume":"191","author":[{"given":"D G","family":"Eglinton","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M K","family":"Johnson","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A J","family":"Thomson","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"P E","family":"Gooding","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C","family":"Greenwood","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/191\/2\/319\/575360\/bj1910319.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/191\/2\/319\/575360\/bj1910319.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,25]],"date-time":"2021-11-25T14:12:39Z","timestamp":1637849559000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/191\/2\/319\/17781\/Near-infrared-magnetic-and-natural-circular"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1980,11,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1980,11,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj1910319","relation":{},"ISSN":["0264-6021"],"issn-type":[{"value":"0264-6021","type":"print"}],"subject":[],"published":{"date-parts":[[1980,11,1]]}}}