Identification and Characterization of the Two-Enzyme System Catalyzing Oxidation of EDTA in the EDTA-Degrading Bacterial Strain DSM 9103
Identification and Characterization of the Two-Enzyme System Catalyzing Oxidation of EDTA in the EDTA-Degrading Bacterial Strain DSM 9103
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EDTA 降解菌株 DSM 9103 中催化 EDTA 氧化的双酶系统的鉴定和表征
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通讯作者：
Christina E. Odeh
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作者：
Allison Gladfelter;E. Johnson;Christina E. Odeh
在一株能以乙二胺四乙酸乙酯为唯一碳源、氮源和能源生长的革兰氏阴性菌(DSM9103)中，阐明了乙二胺四乙酸二乙酯分解代谢途径的第一步fi。它们包括两个乙酰基的顺序氧化去除，导致乙醛的形成。对催化脱乙酰基的酶复合体进行了fi纯化和表征。反应中生成中间体乙二胺三乙酸酯(ED3A)，最终产物为N，N*-乙二胺二乙酸酯。该酶复合体由A组分(CA*)和B组分(CB*)和B组分(CB*)组成。A*(CA*)是一种单加氧酶，它能催化EDTA和ED3A的裂解，同时还能消耗氧气和还原fl。CB*可被其他NADH2：FMN氧化还原酶所取代，如三乙酸氮酯单氧酶的B组分或发光菌fischeri的NADH2：FMN氧化还原酶。EDTA-氧化酶复合体只有在与镁21、锌21、锰21、钴21或铜21络合时才能接受EDTA为底物。此外，该酶复合体还催化从其他几种氨基多羧酸中脱除乙酰基。
In a gram-negative isolate (DSM 9103) able to grow with EDTA as the sole source of carbon, nitrogen, and energy, the first two steps of the catabolic pathway for EDTA were elucidated. They consisted of the sequential oxidative removal of two acetyl groups, resulting in the formation of glyoxylate. An enzyme complex that catalyzes the removal of two acetyl groups was purified and characterized. In the reaction, ethylenediaminetriacetate (ED3A) was formed as an intermediate and N,N * -ethylenediaminediacetate was the end product. The enzyme complex consisted of two components: component A * (cA * ), most likely a monooxygenase, which catalyzes the cleavage of EDTA and ED3A while consuming oxygen and reduced flavin mononucleotide (FMN)-H 2 , and component B * (cB * ), an NADH 2 :FMN oxidoreductase that provides FMNH 2 for cA * . cB * could be replaced by other NADH 2 :FMN oxidoreductases such as component B of the nitrilotriacetate monooxygen- ase or the NADH 2 :FMN oxidoreductase from Photobacterium fischeri . The EDTA-oxidizing enzyme complex accepted EDTA as a substrate only when it was complexed with Mg 2 1 , Zn 2 1 , Mn 2 1 , Co 2 1 , or Cu 2 1 . Moreover, the enzyme complex catalyzed the removal of acetyl groups from several other aminopolycarboxylic