Huang ShuoHao, Yang HuanHuan, Yao LiLi, Zhang JianYun, Huang LongQuan
School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, People's Republic of China; Center for Cell and Gene Therapy, Takara Bio Inc., Seta 3-4-1, Otsu, Shiga 520-2193, Japan.
School of Tea and Food Science, Anhui Agricultural University, Hefei 230036, People's Republic of China.
Comp Biochem Physiol B Biochem Mol Biol. 2016 Apr-May;194-195:20-4. doi: 10.1016/j.cbpb.2016.01.002. Epub 2016 Jan 11.
Vitamin B6 includes 6 pyridine derivatives, among which pyridoxal 5'-phosphate is a coenzyme for over 140 enzymes. Animals acquire their vitamin B6 from food. Through a salvage pathway, pyridoxal 5'-phosphate is synthesized from pyridoxal, pyridoxine or pyridoxamine, in a series of reactions catalyzed by pyridoxal kinase and pyridoxine 5'-phosphate oxidase. The regulation of pyridoxal 5'-phospahte biosynthesis and pyridoxal 5'-phospahte homeostasis are at the center of study for vitamin B6 nutrition. How pyridoxal 5'-phosphate biosynthesis is regulated by hormones has not been reported so far. Our previous studies have shown that pyridoxal 5'-phosphate level in silkworm larva displays cyclic developmental changes. In the current study, effects of exogenous juvenile hormone and molting hormone on the transcription level of genes coding for the enzymes involved in the biosynthesis of pyridoxal 5'-phospahte were examined. Results show that pyridoxal kinase and pyridoxine 5'-phosphate oxidase are regulated at the transcription level by development and are responsive to hormones. Molting hormone stimulates the expression of genes coding for pyridoxal kinase and pyridoxine 5'-phosphate oxidase, and juvenile hormone appears to work against molting hormone. Whether pyridoxal 5'-phosphate biosynthesis is regulated by hormones in general is an important issue for further studies.
维生素B6包括6种吡啶衍生物，其中5'-磷酸吡哆醛是140多种酶的辅酶。动物从食物中获取维生素B6。通过一条补救途径，5'-磷酸吡哆醛由吡哆醛、吡哆醇或吡哆胺合成，这一系列反应由吡哆醛激酶和5'-磷酸吡哆醇氧化酶催化。5'-磷酸吡哆醛生物合成的调控以及5'-磷酸吡哆醛的体内平衡是维生素B6营养研究的核心。到目前为止，尚未有关于5'-磷酸吡哆醛生物合成如何受激素调控的报道。我们之前的研究表明，家蚕幼虫体内5'-磷酸吡哆醛水平呈现周期性的发育变化。在本研究中，检测了外源保幼激素和蜕皮激素对参与5'-磷酸吡哆醛生物合成的酶编码基因转录水平的影响。结果表明，吡哆醛激酶和5'-磷酸吡哆醇氧化酶在转录水平上受发育调控且对激素有反应。蜕皮激素刺激吡哆醛激酶和5'-磷酸吡哆醇氧化酶编码基因的表达，而保幼激素似乎起拮抗蜕皮激素的作用。5'-磷酸吡哆醛生物合成是否普遍受激素调控是有待进一步研究的重要问题。
