{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T13:00:54Z","timestamp":1791896454229,"version":"4.3.4"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"1","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2004,4,1]]},"abstract":"<jats:p>DPD (dihydropyrimidine dehydrogenase) constitutes the first step of the pyrimidine degradation pathway, in which the pyrimidine bases uracil and thymine are catabolized to \u03b2-alanine and the R-enantiomer of \u03b2-AIB (\u03b2-aminoisobutyric acid) respectively. The S-enantiomer of \u03b2-AIB is predominantly derived from the catabolism of valine. It has been suggested that an altered homoeostasis of \u03b2-alanine underlies some of the clinical abnormalities encountered in patients with a DPD deficiency. In the present study, we demonstrated that only a slightly decreased concentration of \u03b2-alanine was present in the urine and plasma, whereas normal levels of \u03b2-alanine were present in the cerebrospinal fluid of patients with a DPD deficiency. Therefore the metabolism of \u03b2-alanine-containing peptides, such as carnosine, may be an important factor involved in the homoeostasis of \u03b2-alanine in patients with DPD deficiency. The mean concentration of \u03b2-AIB was approx. 2\u20133-fold lower in cerebrospinal fluid and urine of patients with a DPD deficiency, when compared with controls. In contrast, strongly decreased levels (10-fold) of \u03b2-AIB were present in the plasma of DPD patients. Our results demonstrate that, under pathological conditions, the catabolism of valine can result in the production of significant amounts of \u03b2-AIB. Furthermore, the observation that the R-enantiomer of \u03b2-AIB is abundantly present in the urine of DPD patients suggests that significant cross-over exists between the thymine and valine catabolic pathways.<\/jats:p>","DOI":"10.1042\/bj20031463","type":"journal-article","created":{"date-parts":[[2004,4,13]],"date-time":"2004-04-13T15:13:59Z","timestamp":1081869239000},"page":"119-124","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":54,"title":["New insights in dihydropyrimidine dehydrogenase deficiency: a pivotal role for beta-aminoisobutyric acid?"],"prefix":"10.1042","volume":"379","author":[{"given":"Andr\u00e9 B. P.","family":"van KUILENBURG","sequence":"first","affiliation":[{"name":"Emma Children's Hospital and Department of Clinical Chemistry, Academic Medical Center, University of Amsterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alida E. M.","family":"STROOMER","sequence":"additional","affiliation":[{"name":"Emma Children's Hospital and Department of Clinical Chemistry, Academic Medical Center, University of Amsterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Henk","family":"van LENTHE","sequence":"additional","affiliation":[{"name":"Emma Children's Hospital and Department of Clinical Chemistry, Academic Medical Center, University of Amsterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nico G. G. M.","family":"ABELING","sequence":"additional","affiliation":[{"name":"Emma Children's Hospital and Department of Clinical Chemistry, Academic Medical Center, University of Amsterdam, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Albert H.","family":"van GENNIP","sequence":"additional","affiliation":[{"name":"Departments of Clinical Genetics and Clinical Chemistry, Academic Hospital Maastricht, Maastricht, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/379\/1\/119\/713081\/bj3790119.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/379\/1\/119\/713081\/bj3790119.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,22]],"date-time":"2021-11-22T13:58:13Z","timestamp":1637589493000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/379\/1\/119\/43200\/New-insights-in-dihydropyrimidine-dehydrogenase"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,4,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2004,4,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj20031463","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,4,1]]}}}