Data/hora: 03/06/2024 02:52:12

Provedor de dados: | 59
País: | Brazil
Título: | Catabolism of caffeine and purification of a xanthine oxidade responsible for methyluric acids production in Pseudomonas putida L
Autores: | Yamaoka-Yano,Dirce Mithico; Mazzafera,Paulo.
Data: | 1999-01-01
Ano: | 1999
Palavras-chave: | Caffeine; Methylpurines; Methyluric acids; Pseudomonas; Xanthine oxidase.
Resumo: | Caffeine catabolism and a xanthine oxidase involved in the alkaloid breakdown were studied in Pseudomonas putida L, a strain displaying high ability to grow on this substrate. Cells cultured with unlabelled caffeine and 14C labeled caffeine and xanthine showed that this alkaloid was broken-down via theobromine/paraxanthine -&amp;gt; 7-methylxanthine -&amp;gt; xanthine -&amp;gt; uric acid -&amp;gt; allantoin -&amp;gt; allantoic acid. Methyluric acids were formed from the oxidation of theobromine, paraxanthine and 7-methylxanthine, although no bacterial growth was observed on these compounds, indicating that this might be due to a wide substrate specificity of xanthine oxidase. This was confirmed by activity staining in PAGE where activity was observed with theophylline and 3-methylxanthine, which are not involved in the alkaloid breakdown. A single band of activity was detected without addition of NAD+, showing an oxidase form of the enzyme. The enzyme optimum temperature and pH were 30oC and 7.0, respectively. The determined Km was 169 µM, and the pI 3.1 - 4.0. The molecular weight determined by side by side comparison of activity staining of the enzyme in PAGE and PAGE of BSA was 192 kDa, which was coincident with the sum (198.4 kDa) of three subunits (71, 65.6 and 61.8 kDa) of the purified protein.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37141999000100013
Editor: | Sociedade Brasileira de Microbiologia
Relação: | 10.1590/S0001-37141999000100013
Formato: | text/html
Fonte: | Revista de Microbiologia  v.30 n.1 1999
Fonte: | info:eu-repo/semantics/openAccess