Shiraishi T, Fukusaki E, Kobayashi A
Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
J Biosci Bioeng. 2000;89(3):241-6. doi: 10.1016/s1389-1723(00)88826-x.
NAD-dependent formate dehydrogenase (FDH, EC 1.2.1.2.) plays a key role in the final step of the catabolism of methanol in methylotrophs. In certain plant species, this enzyme is a mitochondrial and NAD-dependent enzyme. In this study, the complete cDNA sequence of the rice (Oryza sativa cv Hinohikari) FDH gene, which contains an open reading frame (ORF) of 1128 bp, was determined. The sequence corresponds to a protein of 376 amino acids and shows strong homology to the NAD-dependent FDHs from other plants. Our experimental results showed that the expression of the rice cDNA in Escherichia coli induced FDH activity, indicating that the cDNA encodes a functional peptide of FDH. The application of formate to the roots of rice seedlings leads to growth increment both in terms of the length of the aerial part and the fresh weight. The FDH activity and the accumulation of FDH transcripts were strongly enhanced in the root portions of the formate-fed plants. This enhancement indicates that the transcriptional regulation which responds to formate functions in the rice plant, and that formate can act as an effective inducer for FDH activity.
NAD 依赖型甲酸脱氢酶（FDH，EC 1.2.1.2.）在甲基营养菌甲醇分解代谢的最后一步中起关键作用。在某些植物物种中，这种酶是一种线粒体且依赖 NAD 的酶。在本研究中，测定了水稻（Oryza sativa cv Hinohikari）FDH 基因的完整 cDNA 序列，其包含一个 1128 bp 的开放阅读框（ORF）。该序列对应一个 376 个氨基酸的蛋白质，与其他植物的 NAD 依赖型 FDH 具有高度同源性。我们的实验结果表明，水稻 cDNA 在大肠杆菌中的表达诱导了 FDH 活性，这表明该 cDNA 编码 FDH 的一个功能肽。将甲酸盐施用于水稻幼苗的根部，无论是地上部分的长度还是鲜重都导致生长增加。在施用甲酸盐的植物根部，FDH 活性和 FDH 转录本的积累显著增强。这种增强表明水稻植株中存在对甲酸盐作出反应的转录调控，并且甲酸盐可以作为 FDH 活性的有效诱导剂。
