Analysis of sorbitol metabolism in genus Gluconobacter.

结果表明，d -山梨醇而非l -山梨醇是fad -山梨醇脱氢酶（SLDH）基因sldSLC的诱导剂，sldSLC是由d -山梨醇生成l -山梨醇的基因。结果发表。pq -甘油脱氢酶（GLDH）也能从d -山梨醇中生成l -山梨糖，它与细胞色素bo3末端氧化酶的连接效率高，能量保存率高，在l -山梨糖的生成中起主要作用。另一方面，FAD-SLDH与氰化物不敏感末端氧化酶（CIO）结合较好。结果发表。从大肠杆菌转化中表达和纯化的sba酶显示nadph依赖性l -山梨糖还原酶（NADPH-SR）活性。并发表了所得结果。逆转录- pcr实验表明，sboRA含有一个操纵子。预计SboR是一种与L-sorbose结合的转录调节因子。从大肠杆菌转化中表达和纯化了SboR，并将含有sboRA启动子-操作子区域的DNA片段用于凝胶转移试验，然而，我们未能证明SboR具有与L-sorbose或不含L-sorbose的DNA片段结合的能力。结果发表。克隆了d -葡萄糖酸脱氢酶（GADH）基因，并对其进行了测序。为了方便测定5-酮葡萄糖酸盐（5KGA）和2-酮葡萄糖酸盐（2KGA），我们克隆了5KGA还原酶和2KGA还原酶基因，并在大肠杆菌中进行了表达。

It is revealed that D-sorbitol, not L-sorbose, is the inducer of sldSLC, the gene for FAD-sorbitol dehydrogenase (SLDH), yielding L-sorbose from D-sorbitol. The obtained results were published.PQQ-glycerol dehydrogenase (GLDH), yielding also L-sorbose from D-sorbitol, connects efficiently to cytochrome bo 3 terminal oxidase and higher energy conservation ratio, thus it plays a major role in L-sorbose production. On the other hand, FAD-SLDH linked preferably to the cyanide-insensitive terminal oxidase, CIO. The obtained results were published.The SboA enzyme expressed and purified from an Escherichia coli transformant showed NADPH-dependent L-sorbose reductase (NADPH-SR) activity. The obtained results are published. Now the enzyme is served for structural analysis by x-ray crystallographyReverse transcription-PCR experiments indicated that sboRA comprises an operon. It is expected that SboR is a transcriptional regulator which binds with L-sorbose. SboR was expressed and purified from E. coli transformant and used for gel-shift assay with the DNA fragment containing the promoter-operator region for sboRA, however, we failed to demonstrate that SboR has an ability to bind the DNA fragment with or without L-sorbose. The obtained results were published.The gene for FAD-gluconate dehydrogenase (GADH), yielding 2-ketogluconic acid from D-gluconate, was cloned and sequenced.For easy measurement for 5-ketogluconate (5KGA) and 2-ketogluconate (2KGA), genes for 5KGA reductase and 2KGA reductase were cloned and expressed in E. coli, Both enzyme preparations were easily obtained from E. coli transformants after one column chromatography.