Distinct physiological roles of two membrane-bound dehydrogenases responsible for D-sorbitol oxidation in Gluconobacter frateurii
Distinct physiological roles of two membrane-bound dehydrogenases responsible for D-sorbitol oxidation in Gluconobacter frateurii
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DOI：
10.1271/bbb.70720
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发表时间：
2008-03-01
影响因子：
1.6
通讯作者：
Toyama, Hirohide
中科院分区：
文献类型：
--
作者：
Soemphol, Wichai;Adachi, Osao;Toyama, Hirohide
在Frateurii THD 32中发现了两种不同的氧化D-山梨醇的膜结合酶：吡咯喹啉醌依赖性甘油脱氢酶（PQQ-GLDH）和FAD依赖性D-山梨醇脱氢酶（FAD-SLDH）。在这项研究中，FAD-SLDH似乎是由L-山梨糖诱导的。在这两种酶的突变体缺陷生长以及野生型菌株没有，表明这两种酶都是生长在D-山梨醇。在PQQ-GLDH缺陷的菌株表现出延迟L-山梨糖生产，和较低的积累，对应于降低D-山梨糖醇氧化酶活性，尽管高D-山梨糖醇脱氢酶活性，观察。在PQQ-GLDH缺陷的突变株中，D-山梨醇的氧化酶活性对氰化物的抗性更强，并且H+/O比低于野生型菌株或FAD-SLDH缺陷的突变株。这些结果表明，PQQ-GLDH有效地连接到细胞色素bo（3）末端氧化酶，并在L-山梨糖的生产中发挥重要作用。另一方面，FAD-SLDH优选连接到氰化物不敏感的末端氧化酶CIO。
Two different membrane-bound enzymes oxidizing D-sorbitol are found in Gluconobacter frateurii THD32: pyroloquinoline quinone-dependent glycerol dehydrogenase (PQQ-GLDH) and FAD-dependent D-sorbitol dehydrogenase (FAD-SLDH). In this study, FAD-SLDH appeared to be induced by L-sorbose. A mutant defective in both enzymes grew as well as the wild-type strain did, indicating that both enzymes are dispensable for growth on D-sorbitol. The strain defective in PQQ-GLDH exhibited delayed L-sorbose production, and lower accumulation of it, corresponding to decreased oxidase activity for D-sorbitol in spite of high D-sorbitol dehydrogenase activity, was observed. In the mutant strain defective in PQQ-GLDH, oxidase activity with D-sorbitol was much more resistant to cyanide, and the H+/O ratio was lower than in either the wild-type strain or the mutant strain defective in FAD-SLDH. These results suggest that PQQ-GLDH connects efficiently to cytochrome bo(3) terminal oxidase and that it plays a major role in L-sorbose production. On the other hand, FAD-SLDH linked preferably to the cyanide-insensitive terminal oxidase, CIO.