{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T12:48:44Z","timestamp":1767962924408,"version":"3.49.0"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"3","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1991,3,15]]},"abstract":"<jats:p>Site-directed mutagenesis was used to determine the functional role of several residues of Streptomyces glaucescens tyrosinase. Replacement of His-37, -53, -193 or -215 by glutamine yields albino phenotypes, as determined by expression on melanin-indicator plates. The purified mutant proteins display no detectable oxy-enzyme and increased Cu lability at the binuclear active site. The carbonyl derivatives of H189Q and H193Q luminesce, with lambda max. displaced more than 25 nm to a longer wavelength compared with native tyrosinase. The remaining histidine mutants display no detectable luminescence. The results are consistent with these histidine residues (together with His-62 and His-189 reported earlier) acting as Cu ligands in the Streptomyces glaucescens enzyme. Conservative substitution of the invariant Asn-190 by glutamine also gives an albino phenotype, no detectable oxy-enzyme and labilization of active-site Cu. The luminescence spectrum of carbonyl-N190Q, however, closely resembles that of the native enzyme under conditions promoting double Cu occupancy of the catalytic site. A critical role for Asn-190 in active-site hydrogen-bonding interactions is proposed.<\/jats:p>","DOI":"10.1042\/bj2740707","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T21:20:16Z","timestamp":1439241616000},"page":"707-713","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":53,"title":["Albino mutants of <i>Streptomyces glaucescens<\/i> tyrosinase"],"prefix":"10.1042","volume":"274","author":[{"given":"M P","family":"Jackman","sequence":"first","affiliation":[{"name":"Biochemisches Institut der Universit\u00e4t Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A","family":"Hajnal","sequence":"additional","affiliation":[{"name":"Biochemisches Institut der Universit\u00e4t Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"K","family":"Lerch","sequence":"additional","affiliation":[{"name":"Biochemisches Institut der Universit\u00e4t Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/274\/3\/707\/604881\/bj2740707.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/274\/3\/707\/604881\/bj2740707.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,23]],"date-time":"2021-11-23T15:12:49Z","timestamp":1637680369000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/274\/3\/707\/26857\/Albino-mutants-of-Streptomyces-glaucescens"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1991,3,15]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1991,3,15]]}},"URL":"https:\/\/doi.org\/10.1042\/bj2740707","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1991,3,15]]}}}