Branchini B R, Hayward M M, Bamford S, Brennan P M, Lajiness E J
Photochem Photobiol. 1989 May;49(5):689-95. doi: 10.1111/j.1751-1097.1989.tb08442.x.
In the course of investigations on the possible involvement of the CIEEL (chemically initiated electron-exchange luminescence) mechanism in firefly bioluminescence, we have synthesized two novel firefly luciferin substrate analogues. D-Naphthylluciferin and D-quinolylluciferin were prepared by condensing D-cysteine with 2-cyano-6-hydroxynaphthalene and 2-cyano-6-hydroxyquinoline, respectively. These analogues are the first examples of bioluminescent substrates for firefly luciferase that do not contain a benzothiazole moiety. Firefly luciferase-catalyzed bioluminescence emission spectra revealed that compared to the normal yellow-green light of luciferin (lambda max = 559 nm), the emission from naphthylluciferin is significantly blue-shifted (lambda max = 524 nm); whereas quinolylluciferin emits orange-red light (lambda max = 608 nm). The fluorescence emission spectra, reaction pH optima, relative light yields, light emission kinetics and KM values of the analogues also were measured and compared to those of luciferin. Neither of the analogues produced the characteristic flash kinetics observed for the natural substrate. Instead, slower rise times to peak emission intensity were recorded. It appears that the formation of an intermediate from the analogue adenylates prior to the addition of oxygen is responsible for the slow rise times. The synthetic substrate analogues described here should be useful for future mechanistic studies.
在对化学引发电子交换发光（CIEEL）机制可能参与萤火虫生物发光的研究过程中，我们合成了两种新型萤火虫荧光素底物类似物。D-萘基荧光素和D-喹啉基荧光素分别通过将D-半胱氨酸与2-氰基-6-羟基萘和2-氰基-6-羟基喹啉缩合制备而成。这些类似物是萤火虫荧光素酶的生物发光底物中首个不含苯并噻唑部分的例子。萤火虫荧光素酶催化的生物发光发射光谱显示，与荧光素的正常黄绿色光（λmax = 559 nm）相比，萘基荧光素的发射显著蓝移（λmax = 524 nm）；而喹啉基荧光素发出橙红色光（λmax = 608 nm）。还测量了这些类似物的荧光发射光谱、反应最适pH值、相对光产率、发光动力学和KM值，并与荧光素的进行了比较。这两种类似物均未产生天然底物所具有的特征性闪光动力学。相反，记录到达到峰值发射强度的上升时间较慢。似乎在添加氧气之前，类似物腺苷酸形成中间体是上升时间较慢的原因。这里描述的合成底物类似物应有助于未来的机理研究。
