Novel scheme for biosynthesis of aryl metabolites from L-phenylalanine in the fungus Bjerkandera adusta
Novel scheme for biosynthesis of aryl metabolites from L-phenylalanine in the fungus Bjerkandera adusta
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DOI：
10.1128/aem.66.4.1517-1522.2000
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发表时间：
2000-04-01
影响因子：
4.4
通讯作者：
Bonnarme, P
中科院分区：
文献类型：
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作者：
Lapadatescu, C;Giniès, C;Bonnarme, P
在添加l -苯丙氨酸的液体培养基中，研究了白腐菌芳基代谢物的生物合成。加入标记的前体（C-14和c -13标记的l -苯丙氨酸）后，用气相色谱-质谱法分析芳香化合物，这些前体不会干扰真菌的代谢。鉴定出的主要芳香化合物为苯甲醇、苯甲醛（苦杏仁香气）和苯甲酸。羟基和甲氧基苯基化合物（醇类、醛类和酸类）也在真菌培养物中发现。测定了adusta培养物胞内酶活性（苯丙氨酸解氨酶、芳基醇氧化酶、芳基醇脱氢酶、芳基醛脱氢酶、木质素过氧化物酶）和胞外酶活性（芳基醇氧化酶、木质素过氧化物酶）及芳香族化合物的含量。代谢产物的形成需要从头合成蛋白质。结果表明：l -苯丙氨酸通过苯丙氨酸解氨酶脱胺生成反式肉桂酸，反式肉桂酸又转化为芳香酸（苯丙酮酸、苯乙酸、扁桃酸和苯甲酰甲酸）；苯甲醛是一种代谢中间体。这些酸转化为苯甲醛、苯甲醇和苯甲酸。我们的研究结果支持了这样的假设，即所有这些化合物都是l -苯丙氨酸到丙氨酸代谢物的生物合成途径中的中间产物。此外，反式肉桂酸也可以通过-氧化转化为苯甲酸。这被苯乙酮作为β -氧化降解中间体的存在所证实。据我们所知，这是第一次在白腐菌中发现导致苯甲酸合成的β -氧化序列。提出了一种新的l -苯丙氨酸生物合成芳基代谢物的代谢方案。
Aryl metabolite biosynthesis was studied in the white rot fungus Bjerkandera adusta cultivated in a liquid medium supplemented with L-phenglalanine. Aromatic compounds were analyzed by gas chromatography-mass spectrometry following addition of labelled precursors (C-14- and C-13-labelled L-phenylalanine), which did not interfere with fungal metabolism. The major aromatic compounds identified were benzyl alcohol, benzaldehyde (bitter almond aroma), and benzoic acid. Hydroxy- and methoxybenzylic compounds (alcohols, aldehydes, and acids) were also found in fungal cultures. Intracellular enzymatic activities (phenylalanine ammonia lyase, aryl-alcohol oxidase, aryl-alcohol dehydrogenase, aryl-aldehyde dehydrogenase, lignin peroxidase) and extracellular enzymatic activities (aryl-alcohol oxidase, lignin peroxidase), as well as aromatic compounds, were detected in B. adusta cultures. Metabolite formation required de novo protein biosynthesis. Our results show that L-phenylalanine was deaminated to trans-cinnamic acid by a phenylalanine ammonia lyase and trans-cinnamic acid was in turn converted to aromatic acids (phenylpyruvic, phenylacetic, mandelic, and benzoylformic acids); benzaldehyde was a metabolic intermediate. These acids were transformed into benzaldehyde, benzyl alcohol, and benzoic acid. Our findings support the hypothesis that all of these compounds are intermediates in the biosynthetic pathway from L-phenylalanine to argl metabolites. Additionally, trans-cinnamic acid can also be transformed via beta-oxidation to benzoic acid. This was confirmed by the presence of acetophenone as a beta-oxidation degradation intermediate. To our knowledge, this is the first time that a beta-oxidation sequence leading to benzoic acid synthesis has been found in a white rot fungus. A novel metabolic scheme for biosynthesis of aryl metabolites from L-phenylalanine is proposed.