4960. Indo-1

Nomenclature

CAS number: 96314-96-4
2-[4-[Bis(carboxymethyl)amino]-3-[2-[2-[bis(carboxymethyl)amino]-5-methylphenoxy]ethoxy]phenyl]-1H-indole-6-carboxylic acid; 1-[2-amino-5-(6-carboxyindol-2-yl)phenoxy]-2-(2′-amino-5-methylphenoxy)ethane-N,N,N′,N′-tetraacetic acid.
C32H31N3O12; mol wt 649.60.
C 59.17%, H 4.81%, N 6.47%, O 29.56%.

Description and references

Fluorescent calcium imaging agent; structurally related to BAPTA, q.v. Ca2+ binding causes a spectral shift to shorter wavelengths; ratio of the fluorescence at each wavelength is related to changes in Ca2+ binding and independent of dye concentration. Synthesis and characterization: G. Grynkiewicz et al., J. Biol. Chem. 260, 3440 (1985). Acid-base and calcium binding properties: F. Bancel et al., J. Photochem. Photobiol. A 53, 397 (1990); spectral properties: H. Szmacinski et al., Biophys. J. 70, 547 (1996). Practical aspects of use in intracellular measurements: K. R. Sipido, G. Callewaert, Cardiovasc. Res. 29, 717 (1995). Detection of other metal cations: G. A. Peeters et al., Am. J. Physiol. 256, C351 (1989); J. R. Jefferson et al., Anal. Biochem. 187, 328 (1990). Review of use in plant cells: D. S. Bush, R. L. Jones, Plant Physiol. 93, 841-845 (1990).

Chemical structure

Properties

uv max absorption (100mM KCl): 349 nm free dye; 331 nm Ca2+ complex; emission maxima: 485 nm free dye; 410 nm Ca2+ complex. pKa1: 6.2; pKa2: 4.35.

Use

Fluorescent probe primarily for measuring calcium in biological systems.