{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T02:20:24Z","timestamp":1767666024058},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"2","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1971,11,1]]},"abstract":"<jats:p>1. Phenylalanine is converted into tyrosine by incubation in air with 6,7-dimethyltetrahydropterin, which is a cofactor for the enzymic hydroxylation. This can cause serious inaccuracies in assays of phenylalanine hydroxylase. 2. The non-enzymic reaction is not specific for l-phenylalanine. 3. m-Tyrosine, o-tyrosine and dihydroxyphenylalanines are formed in addition to p-tyrosine; their chromatographic separation and assay are described. 4. l-[14C]Phenylalanine as purchased or soon after purification contains p- and m-tyrosine, both of which can cause errors in the assay of phenylalanine hydroxylase. 5. Catalase prevents the non-enzymic hydroxylation. Thiol compounds in low concentrations stimulate the reaction but in high concentrations are inhibitory. Fe2+ and metal complexing agents have small stimulatory effects. 6. The mechanism of the non-enzymic reaction and its possible relation to the enzymic hydroxylation of phenylalanine are discussed; it is suggested that phenylalanine is attacked by a peroxide of the cofactor.<\/jats:p>","DOI":"10.1042\/bj1250569","type":"journal-article","created":{"date-parts":[[2015,8,13]],"date-time":"2015-08-13T21:39:23Z","timestamp":1439501963000},"page":"569-574","update-policy":"http:\/\/dx.doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["The non-enzymic hydroxylation of phenylalanine to tyrosine by 2-amino-4-hydroxy-6,7-dimethyl-5,6,7,8-tetrahydropteridine"],"prefix":"10.1042","volume":"125","author":[{"given":"L. I.","family":"Woolf","sequence":"first","affiliation":[{"name":"Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A.","family":"Jakubovi\u010d","sequence":"additional","affiliation":[{"name":"Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"E.","family":"Chan-Henry","sequence":"additional","affiliation":[{"name":"Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, Vancouver, B.C., Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/125\/2\/569\/774138\/bj1250569.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/125\/2\/569\/774138\/bj1250569.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,26]],"date-time":"2021-11-26T15:44:48Z","timestamp":1637941488000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/125\/2\/569\/8511\/The-non-enzymic-hydroxylation-of-phenylalanine-to"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1971,11,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1971,11,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj1250569","relation":{},"ISSN":["0306-3283"],"issn-type":[{"value":"0306-3283","type":"print"}],"subject":[],"published":{"date-parts":[[1971,11,1]]}}}