Firefly luciferase can use L-luciferin to produce light
Firefly luciferase can use L-luciferin to produce light
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DOI：
10.1042/bj3170273
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发表时间：
1996-07-01
影响因子：
4.1
通讯作者：
Lembert, N
中科院分区：
文献类型：
--
作者：
Lembert, N
L-荧光素是萤火虫荧光素酶的竞争性抑制剂，Ki在3和4 μ M之间。此外，L-胰蛋白酶可以作为光产生的替代底物。在不存在或低浓度的D-甜菜碱的情况下可以观察到L-甜菜碱的催化作用。由L-精氨酸产生的光缓慢增加（最大半衰期8分钟）至稳定的平台。在低浓度的酶和L-甜菜碱，最大的光产生是在相应的D-甜菜碱浓度下观察到的光产生的大约一半。增加酶或L-精氨酸的浓度相对于通过D-精氨酸催化获得的光产生减少。与D-荧光素酶在光产生中的催化相反，如果荧光素酶与无机焦磷酸酶（PPi-ase）预混合，则加入PPi可以有效地刺激L-荧光素酶的光产生。如果将PPi注入荧光素酶、L-胰蛋白酶、ATP和PPi酶的混合物中，则会发出闪光。该系统保持其响应性，并在重复添加PPi时发出大约相等持续时间和强度的进一步闪烁。有人提出，PPi诱导酶结合的L-腺苷酸的外消旋化。PPi依赖的细胞内ATP监测的潜在用途进行了讨论。PPi对萤火虫荧光素酶的激活可能是体内闪光调节的一部分。
L-Luciferin is a competitive inhibitor of firefly luciferase with a K-i between 3 and 4 mu M. Furthermore L-luciferin can serve as an alternative substrate for light production. Catalysis of L-luciferin can be observed in the absence of, or at low concentrations of, D-luciferin. The light production from L-luciferin increases slowly (maximal half-time 8 min) to a stable plateau. At low concentrations of enzyme and L-luciferin, maximal light production is about half of that observed at corresponding D-luciferin concentrations. Increasing the concentration of enzyme or L-luciferin reduces the light production relative to that obtained by D-luciferin catalysis. In contrast to the catalysis of D-luciferin the light production from L-luciferin can be effectively stimulated by the addition of PPi provided that luciferase is premixed with inorganic pyrophosphatase (PPi-ase). A flash is emitted if PPi is injected into a mixture of luciferase, L-luciferin, ATP and PPi-ase. The system maintains its responsiveness and emits further flashes of about equal duration and intensity upon repeated additions of PPi. It is proposed that PPi induces a racemization of enzyme-bound L-luciferyl adenylate. The potential usefulness of PPi-dependent intracellular ATP monitoring is discussed. The proposed activation of firefly luciferase by PPi may be part of the regulation of in vivo flashing.