{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,4]],"date-time":"2025-09-04T13:15:18Z","timestamp":1756991718753},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"4","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1971,7,1]]},"abstract":"<jats:p>1. The amino acid composition of the \u03b2-lactamase from E. coli (R-1818) was determined. 2. The R-1818 \u03b2-lactamase is inhibited by formaldehyde, hydroxylamine, sodium azide, iodoacetamide, iodine and sodium chloride. 3. The Km values for benzylpenicillin, ampicillin and oxacillin have been determined by using the R-factor enzyme from different host species. The same values were obtained, irrespective of the host bacterium. 4. The molecular weight of the enzyme was found to be 44600, and was the same for all host species. 5. The relationship of R-1818 and R-GN238 \u03b2-lactamases is discussed.<\/jats:p>","DOI":"10.1042\/bj1230501","type":"journal-article","created":{"date-parts":[[2015,8,13]],"date-time":"2015-08-13T21:37:23Z","timestamp":1439501843000},"page":"501-505","update-policy":"http:\/\/dx.doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":23,"title":["Characterization of the \u03b2-lactamase specified by the resistance factor R-1818 in <i>Escherichia coli<\/i> K12 and other Gram-negative bacteria"],"prefix":"10.1042","volume":"123","author":[{"given":"J. W.","family":"Dale","sequence":"first","affiliation":[{"name":"Microbiology Section, Department of Pharmaceutics, The School of Pharmacy, University of London, London WC1N 1AX, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/123\/4\/501\/771276\/bj1230501.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/123\/4\/501\/771276\/bj1230501.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,26]],"date-time":"2021-11-26T14:48:23Z","timestamp":1637938103000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/123\/4\/501\/7208\/Characterization-of-the-lactamase-specified-by-the"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1971,7,1]]},"references-count":0,"journal-issue":{"issue":"4","published-print":{"date-parts":[[1971,7,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj1230501","relation":{},"ISSN":["0306-3283"],"issn-type":[{"value":"0306-3283","type":"print"}],"subject":[],"published":{"date-parts":[[1971,7,1]]}}}