期刊
JOURNAL OF PINEAL RESEARCH
卷 58, 期 3, 页码 343-351出版社
WILEY
DOI: 10.1111/jpi.12220
关键词
2-hydroxymelatonin; 2-oxoglutarate-dependent dioxygenase; dioxygenase; melatonin catabolism; prohexadione-Ca
资金
- Next Generation BioGreen 21 Program (SSAC Project) [PJ01107201]
- Rural Development Administration
- National Research Foundation (NRF) of Korea through the Ministry of Education, Republic of Korea [2010-0020141, 2014R1A2A1A11050083]
- National Research Foundation of Korea [2014R1A2A1A11050083, 22A20130012880, 2010-0020141] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
Although melatonin biosynthetic genes from plants have been cloned, the melatonin catabolism mechanisms remain unclear. To clone the genes responsible for melatonin metabolism, we ectopically expressed 35 full-length cDNAs of rice 2-oxoglutarate-dependent dioxygenase (2-ODD) in Escherichia coli and purified the corresponding recombinant proteins. In vitro 2-ODD assays showed four independent 2-ODD proteins that were able to catalyze melatonin into 2-hydroxymelatonin, exhibiting melatonin 2-hydroxylase (M2H). These M2H proteins had peak activities at pH 8.0 and 30 degrees C. The K-m ranged from 121m to 371m with the V-max ranging from 1.7 to 18.5 pkat/mg protein, respectively. The M2H enzyme activities were dependent on cofactors such as -ketoglutarate, ascorbate, and Fe2+, similar to the 2-ODD enzymes. M2H activity was inhibited by prohexadione-Ca, an inhibitor of 2-ODD, in a dose-dependent manner. M2H activity was high in the roots of rice seedlings, concurrent with high transcription levels of 2-ODD 21, suggesting that 2-ODD 21 was a major gene for M2H activity. Analogous to the high M2H activity in the roots, 2-hydroxymelatonin was found in large quantities in roots treated with melatonin. These results suggest that melatonin was metabolized into 2-hydroxymelatonin by the M2H genes in plants, but the physiological significance of 2-hydroxymelatonin remains to be examined in the future.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据