Malate dehydrogenase (MDH), which is ubiquitously occurred in nature, catalyzes the interconversion of malate and oxaloacetate. Higher plants contain multiple forms of MDH that differ in coenzyme specificity, subcellular localization and physiological function. A putative Bambusa oldhamii BoMDH cDNA was screened with the specific probe from the bamboo cDNA library. Sequence alignment shows that there's a high homology between the deduced amino acid sequence of BoMDH and MDH protein in Oryza sativa glyoxysome (92%). A 57 kDa fusion protein was expressed by IPTG induction in Escherichia coli BL21 (DE3), and an obvious MDH activity was detected in the recombinant protein. The molecular mass of recombinant BoMDH was estimated to be 120 kDa, and the subunit form was 57 kDa by denatured SDS-PAGE, indicating that BoMDH presents as a homodimer. The optimum temperature and pH for BoMDH activity were 40 °C and 9.5, respectively. The Km values of BoMDH for malate and NAD+ were 5.2 mM and 0.52 mM. The kcat/Km values of BoMDH for malate and NAD+ were 163 min-1 mM-1 and 3060 min-1 mM-1.

中文翻译：

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鲍氏草Bohamdh BoMDH编码的苹果酸脱氢酶的克隆和鉴定。

自然界中普遍存在的苹果酸脱氢酶（MDH）催化苹果酸和草酰乙酸的相互转化。高等植物含有多种形式的MDH，其辅酶特异性，亚细胞定位和生理功能各不相同。用竹子cDNA文库中的特异探针筛选推定的Bambusa oldhamii BoMDH cDNA。序列比对表明，在水稻稻乙醛酸体中BoMDH和MDH蛋白的推导氨基酸序列之间有很高的同源性（92％）。通过IPTG诱导在大肠杆菌BL21（DE3）中表达了57kDa的融合蛋白，并且在重组蛋白中检测到明显的MDH活性。通过变性的SDS-PAGE估计重组BoMDH的分子量为120kDa，亚基形式为57kDa，表明BoMDH以同型二聚体形式存在。BoMDH活性的最佳温度和pH分别为40°C和9.5。苹果酸和NAD +的BoMDH的Km值分别为5.2 mM和0.52 mM。苹果酸和NAD +的BoMDH的kcat / Km值为163 min-1 mM-1和3060 min-1 mM-1。