Emission of methylbutyric acid from Gypsophila paniculata L. during bud opening: Changes in amino acid catabolism
Emission of methylbutyric acid from Gypsophila paniculata L. during bud opening: Changes in amino acid catabolism
复制标题
满天星花芽开放期间甲基丁酸的排放：氨基酸分解代谢的变化
DOI：
10.1016/j.scienta.2005.03.013
复制
发表时间：
2005
影响因子：
4.3
通讯作者：
M. Doi
中科院分区：
文献类型：
--
作者：
H. Nimitkeatkai;Y. Ueda;H. Furukawa;K. Inamoto;M. Doi
为阐明石竹花序异味产生的甲基丁酸释放机理。布里斯托尔仙女和戈兰)，我们研究了支链氨基酸分解代谢途径中的酶的活性。连续喷施10 mM L-亮氨酸、10 mM L-异亮氨酸或4.5 mM异戊醛均能增加甲基丁酸的产量。用异戊醛处理绞股蓝花序时，在气相色谱图上也出现了一个大的异戊醇峰。无香、紧实和膨大的花蕾中丙酮酸脱羧酶(PDC)和乙醇脱氢酶(ADH)活性较高，开放小花中这些酶的活性较低。另一方面，丙酮酸脱氢酶(PDH)和酰辅酶A水解酶(ACH)活性在花蕾开放期间呈上升趋势。乙醛氧化酶(AO)和乙醛脱氢酶(ALDH)活性在整个蕾期较低。这些结果表明，L-亮氨酸等支链氨基酸在石竹花序中的分解代谢有两条可能的途径。第一条路线在开花前很活跃，它最终通过异戊醛和脱氢酶将L-亮氨酸转化为异戊醇。第二条途径是通过PDH和ACH通过异戊基辅酶A将亮氨酸转化为3-甲基丁酸，在开放的小花中变得活跃。从第一条途径到第二条途径的变化可能与开放小花释放的甲基丁酸的增加有关。
To elucidate the mechanism of methylbutyric acid emission which is responsible for the unpleasant odor of gypsophila inflorescences (Gypsophila paniculata L. ‘Bristol Fairy’ and ‘Golan’), we investigated the activities of enzymes in the catabolic pathway of branched-chain amino acids. The continuous application of either 10mM l-leucine, 10mM l-isoleucine or 4.5mM isovaleraldehyde increased the production of methylbutyric acids. When gypsophila inflorescences were treated with isovaleraldehyde, a large peak of isoamyl alcohol also appeared on the gas chromatogram. High activities of pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH) were detected in nonscented, tight and swollen buds, but the activities of these enzymes decreased in open florets. On the other hand, the activities of pyruvate dehydrogenase (PDH) and acyl-CoA hydrolase (ACH) increased during bud opening. The activities of aldehyde oxidase (AO) and aldehyde dehydrogenase (ALDH) were low throughout bud opening. These results indicate that the catabolism of branched-chain amino acids such as l-leucine in gypsophila inflorescences have two potential catabolic pathways. The first route, which finally converts l-leucine to isoamyl alcohol via isovaleraldehyde by PDC and ADH, is active before anthesis. The second route, which converts leucine to 3-methylbutyric acid via isovaleryl-CoA by PDH and ACH, becomes active in open florets. The alternation from the first to second route may correlate with the increase in emission of methylbutyric acids from open florets.