VANILLIC ACID METABOLISM BY THE WHITE-ROT FUNGUS SPOROTRICHUM-PULVERULENTUM
VANILLIC ACID METABOLISM BY THE WHITE-ROT FUNGUS SPOROTRICHUM-PULVERULENTUM
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DOI：
10.1007/bf00446876
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发表时间：
1980-01-01
影响因子：
2.8
通讯作者：
ERIKSSON, KE
中科院分区：
文献类型：
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作者：
ANDER, P;HATAKKA, A;ERIKSSON, KE
研究了野生型粉孢霉（Sporotrichum pulverulentum）和3种不同突变体的香草酸代谢。香草酸被发现是氧化脱羧甲氧基氢醌（MHQ），同时减少香草醛和香草醇不同程度地取决于培养条件。还原途径不能被利用，除非真菌能够获得容易代谢的碳源，如葡萄糖或纤维二糖，而脱羧作用发生在仅存在香草酸的培养物中。聚合反应也发生在培养液中。用辣根过氧化物酶进行的离体实验和体内实验表明，香草醛和香草醇的再氧化反应是在羧基、甲氧基和芳环上标记的香草酸发生脱羧反应，而脱羧反应发生在开环之前，这又比O_（14）CH_3-香草酸释放~（14）CO_2的时间早。与0.25%纤维二糖相比，1%纤维二糖抑制了甲氧基的14 CO2释放，但与2.6 mM氮相比，26 mM氮（如天冬酰胺加NH 4 NO3）刺激了甲氧基的14 CO2释放。自从。由于在开环之前需要有三个羟基连接在苯环上，开环的准备工作显然是通过羟基化而不是去甲基化来完成的。根据这些结果提出了一种粉末。
Vanillic acid metabolism was studied in wild-typeSporotrichum pulverulentumand three different mutants. Vanillic acid was found to be oxidatively decarboxylated to methoxyhydroquinone (MHQ) and simultaneously reduced to vanillin and vanillyl alcohol to different degrees depending upon the cultivation conditions. The reducing pathway cannot be utilized unless the fungus has access to an easily metabolized carbon source such as glucose or cellobiose, while decarboxylation takes place in cultures with only vanillic acid present. Polymerization reactions also occurred in the culture solutions. Some evidence for reoxidation of vanillin and vanillyl alcohol was obtained in vivo, and in vitro experiments using horseradish peroxidase.Using vanillic acids labelled in the carboxyl, methoxyl and the aromatic ring it was shown that decarboxylation occures before ring-cleavage, which in turn takes place earlier than the release of14CO2from O14CH3-vanillate. The14CO2evolution from the methoxyl group is repressed by 1% cellobiose as compared to 0.25% cellobiose, but is stimulated by 26 mM nitrogen (as asparagine plus NH4NO3) compared to 2.6 mM nitrogen. SinceS. pulverulentumappears to require three hydroxyl groups attached to the benzene ring before ring-cleavage can occur, preparation for ring-cleavage is apparently achieved by hydroxylation rather than by demethylation.A scheme for metabolism of vanillic acid byS. pulverulentumbased upon these results is proposed.