Department of Microbiology, Miami University, 45056, Oxford, OH, USA.
Plant Mol Biol. 1985 Jul;4(4):197-204. doi: 10.1007/BF02418236.
A detailed characterization of the lysine biosynthetic pathway in plants is yet to be completed. It is, however, assumed that the diaminopimelic acid pathway exists in the plant kingdom, as commonly described forEscherichia coli.Modification and refinement of lytic complementation, a technique previously utilized in bacterial systems, facilitated the isolation of a functional Diaminopimelate Dehydrogenase gene from aGlycine max nuclear gene library. The isolated gene codes for the enzyme meso-diaminopimelate dehydrogenase. The coding capacity for the enzyme was originally contained on a 6.6kb fragment in a Charon 4a soybean gene bank. Subcloning of the 6.6kb fragment resulted in the recombinant plasmid pMW75. Subsequent subcloning resulted in a 4.05 kb fragment contained in pLW14. One region of homology was observed upon hybridization to EcoR1 digested soybean DNA. Homologous sequences were also observed in Triticum DNA.Meso-diaminopimelate dehydrogenase activity was demonstrated inGlycine max embryos. Maximum enzymatic activity of the cloned enzyme was observed at a pH of 8.0. The enzyme encoded by the soybean gene has an apparent molecular weight of 67 000.
植物赖氨酸生物合成途径的详细特征尚未完全确定。然而，人们普遍认为，正如大肠杆菌中所描述的那样，二氨基庚二酸途径存在于植物界。溶菌互补法的改进和完善，这项技术以前曾用于细菌系统，有助于从大豆核基因文库中分离出具有功能的二氨基庚二酸脱氢酶基因。分离出的基因编码酶中间二氨基庚二酸脱氢酶。该酶的编码能力最初包含在大豆载体 4a 的一个 6.6kb 片段中。6.6kb 片段的亚克隆导致重组质粒 pMW75 的产生。随后的亚克隆导致包含在 pLW14 中的 4.05kb 片段。在与 EcoR1 消化的大豆 DNA 杂交时观察到一个同源区域。在小麦 DNA 中也观察到了同源序列。在大豆胚胎中证明了中间二氨基庚二酸脱氢酶的活性。克隆酶的最大酶活性在 pH8.0 时观察到。由大豆基因编码的酶的表观分子量为 67000。
