Faculty of Agriculture, Kyushu University Graduate School, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
Laboratory of Biochemistry, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, 501-1196, Japan.
Chem Biol Interact. 2022 Jan 5;351:109717. doi: 10.1016/j.cbi.2021.109717. Epub 2021 Oct 28.
Lepidopterans are agricultural pests. Since the silkworm is a model for lepidopterans, analysis of the enzymes produced by silkworms is of great interest for developing methods of pest control. The aldo-keto reductase (AKR) superfamily catalyzes the reduction of aldehydes by converting a carbonyl group to an alcohol group. Here, we characterized a new AKR present in the silkworm Bombyx mori, which has been designated as AKR2E8. Amino acid sequence and phylogenetic analyses showed that AKR2E8 is similar to human AKR1B1 and AKR1B10. Three amino acid residues in the active site were identical among AKR2E8, AKR1B1, and AKR1B10. Recombinant AKR2E8 overexpressed in Escherichia coli used nicotinamide adenine dinucleotide phosphate as a coenzyme to reduce the aldehydes present in mulberry (Morus alba) leaves. AKR2E8 was found to reduce benzaldehyde, hexanal, heptanal, nonanal, trans-2-nonenal, and citral. No nicotinamide adenine dinucleotide-dependent activity was detected. Akr2e8 mRNA was detected in the testes, ovaries, and fat body; the highest expression was found in the midgut. The substrate specificity and highest observed expression of AKR2E8 in the midgut suggests that AKR2E8 may play a major role in aldehyde detoxification in silkworms. The findings of this study may assist in the development of pest control methods for controlling the population of lepidopterans, such as silkworms, that damage crops.
鳞翅目昆虫是农业害虫。由于家蚕是鳞翅目的模式生物，因此分析家蚕产生的酶对于开发害虫防治方法具有重要意义。醛酮还原酶（AKR）超家族通过将羰基转化为醇基来催化醛的还原。在这里，我们鉴定了一种存在于家蚕 Bombyx mori 中的新 AKR，将其命名为 AKR2E8。氨基酸序列和系统发育分析表明，AKR2E8 与人类 AKR1B1 和 AKR1B10 相似。AKR2E8、AKR1B1 和 AKR1B10 的活性位点中有三个氨基酸残基相同。在大肠杆菌中过表达的重组 AKR2E8 利用烟酰胺腺嘌呤二核苷酸磷酸作为辅酶还原桑叶中的醛。发现 AKR2E8 还原苯甲醛、己醛、庚醛、壬醛、反式-2-壬烯醛和柠檬醛。未检测到烟酰胺腺嘌呤二核苷酸依赖性活性。在睾丸、卵巢和脂肪体中检测到 Akr2e8 mRNA；在中肠中表达最高。AKR2E8 在中肠中的底物特异性和最高表达表明，AKR2E8 可能在家蚕醛解毒中发挥主要作用。本研究的结果可能有助于开发控制鳞翅目害虫（如破坏作物的家蚕）种群的害虫防治方法。
