[Alexa Fluor dyes]

明るく安定した蛍光を発する色素。

【分類】

名称 吸光 蛍光 吸光係数
1　Alexa Fluor® 350 346 442　19,000
2　Alexa Fluor® 405 401 421　34,000
3　Alexa Fluor® 430 433 541　16,000
4　Alexa Fluor® 488 495 519　71,000
5　Alexa Fluor® 532 532 553　81,000
6　Alexa Fluor® 546 556 573 104,000
　　fading problems reported
7　Alexa Fluor® 555 555 565 150,000
8　Alexa Fluor® 568 578 603　91,300
9　Alexa Fluor® 594 590 617　73,000
10 Alexa Fluor® 633 632 647 100,000
11 Alexa Fluor® 647 650 665 239,000
12 Alexa Fluor® 680 679 702 184,000
13 Alexa Fluor® 700 702 723 192,000
14 Alexa Fluor® 750 749 775 240,000
15 Alexa Fluor® 790 785 810 260,000

【特徴】

　◆強力な吸光
　◆明るく極めて光安定
　◆水溶性

Well-differentiated spectra, providing many options for multicolor detection and fluorescence resonance energy transfer (Fluorescence Resonance Energy Transfer (FRET)—Note 1.2)
High quantum yields and long fluorescence lifetimes (Fluorescence quantum yields (QY) and lifetimes (T) for Alexa Fluor dyes—Table 1.5)
Extremely high FRET efficiency, with calculated R0 values of up to 84 Å between pairs of Alexa Fluor dyes (R<0> values for some Alexa Fluor dyes—Table 1.6) and up to 77 Å between Alexa Fluor dyes and some nonfluorescent quenchers (R<0> values for QSY and dabcyl quenchers—Table 1.11)

Alexa Fluor dyes set new standards for fluorophores and the bioconjugates prepared from them (The Alexa Fluor Dye Series—Note 1.1). The absorption spectra (Figure 1.34, Figure 1.17, Figure 1.24) of these superior fluorescent dyes—Alexa Fluor 350, Alexa Fluor 405, Alexa Fluor 430, Alexa Fluor 488, Alexa Fluor 514, Alexa Fluor 532, Alexa Fluor 546, Alexa Fluor 555, Alexa Fluor 568, Alexa Fluor 594, Alexa Fluor 610, Alexa Fluor 633, Alexa Fluor 635, Alexa Fluor 647, Alexa Fluor 660, Alexa Fluor 680, Alexa Fluor 700, Alexa Fluor 750 and Alexa Fluor 790 dyes—span the visible and infrared spectrum (Alexa Fluor active esters and kits for labeling proteins and nucleic acids—Table 1.4) and match the principal output wavelengths of common excitation sources. Because there are so many different Alexa Fluor dyes, we have had to develop a systematic strategy for naming them. We identify these dyes with the registered trademark Alexa Fluor followed by the optimal excitation wavelength in nm; for example, Alexa Fluor 488 dye is optimally excited by the 488 nm spectral line of the argon-ion laser.

With spectra almost identical to those of fluorescein (Figure 1.8), but with far greater conjugate fluorescence and significantly better conjugate photostability, Alexa Fluor 488 dye is indisputably the best green-fluorescent reactive dye available. Spectra of Alexa Fluor 555 dye are an almost perfect match to those of Cy3 dye (Figure 1.18), but conjugates of Alexa Fluor 555 dye are more fluorescent (Figure 1.29) and more photostable (Figure 1.20) than those of Cy3 dye. Similarly, spectra of Alexa Fluor 647 conjugates substantially match those of the Cy5 dye (Figure 1.25) and Alexa Fluor 680 and Alexa Fluor 750 dyes exhibit spectral properties similar to those of Cy5.5 and Cy7 dyes, respectively (Figure 1.26, Figure 1.27). Tandem conjugates of the long-wavelength Alexa Fluor dyes with R-phycoerythrin or allophycocyanin (Phycobiliproteins—Section 6.4) further expand the utility of this dye series in multiplex flow cytometry applications by shifting the phycobiliprotein emission profile relative to the available detection channels (Figure 6.34, Figure 6.37).