Huang ShuoHao, Han CaiYun, Ma ZhenQiao, Zhou Jie, Zhang JianYun, Huang LongQuan
School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei 230036, People's Republic of China.
School of Foreign Languages, Anhui Agricultural University, Hefei 230036, People's Republic of China.
Comp Biochem Physiol B Biochem Mol Biol. 2017 Mar;205:39-45. doi: 10.1016/j.cbpb.2017.01.003. Epub 2017 Jan 10.
Vitamin B comprises six interconvertible pyridine compounds, among which pyridoxal 5'-phosphate (PLP) is a coenzyme for over 140 enzymes. PLP is also a very reactive aldehyde. The most well established mechanism for maintaining low levels of free PLP is its dephosphorylation by phosphatases. A human PLP-specific phosphatase has been identified and characterized. However, very little is known about the phosphatase in other living organisms. In this study, a cDNA clone of putative PLP phosphatase was identified from B. mori and characterized. The cDNA encodes a polypeptide of 343 amino acid residues, and the recombinant enzyme purified from E. coli exhibited properties similar to that of human PLP phosphatase. B. mori has a single copy of the PLPP gene, which is located on 11th chromosome, spans a 5.7kb region and contains five exons and four introns. PLP phosphatase transcript was detected in every larva tissue except hemolymph, and was most highly represented in Malpighian tube. We further down-regulated the gene expression of the PLP phosphatase in 5th instar larvae with the RNA interference. However, no significant changes in the gene expression of PLP biosynthetic enzymes and composition of B vitamers were detected as compared with the control.
维生素B由六种可相互转化的吡啶化合物组成，其中5'-磷酸吡哆醛（PLP）是140多种酶的辅酶。PLP也是一种活性很强的醛。维持游离PLP低水平的最成熟机制是其被磷酸酶去磷酸化。一种人PLP特异性磷酸酶已被鉴定和表征。然而，对于其他生物体中的磷酸酶却知之甚少。在本研究中，从家蚕中鉴定并表征了一个假定的PLP磷酸酶的cDNA克隆。该cDNA编码一个由343个氨基酸残基组成的多肽，从大肠杆菌中纯化的重组酶表现出与人PLP磷酸酶相似的特性。家蚕有一个PLPP基因的单拷贝，位于第11号染色体上，跨度为5.7kb区域，包含五个外显子和四个内含子。除血淋巴外，在每个幼虫组织中都检测到了PLP磷酸酶转录本，并且在马氏管中表达量最高。我们通过RNA干扰进一步下调了五龄幼虫中PLP磷酸酶的基因表达。然而，与对照组相比，未检测到PLP生物合成酶的基因表达和B族维生素组成的显著变化。
