Thio-H

This is a new Calcium indicator with promising properties which provide an excellent addition to fluorescent Ca²⁺/Mg²⁺ indicators available already. It is a low-affinity Ca²⁺-indicators (K_d ca 55 μM). Such indicators are useful for determination of Ca²⁺ in intracellular compartments [or for monitoring steep increases in intracellular concentration of Ca²⁺ .
Compared to wellknown low-affinity Ca²⁺ indicators Thio-H is about three times brighter. This is based on strong molar absorption as well as high quantum yields. High fluorescent output allows low indicator concentrations to be used, which decreases the cation buffering effects of indicator. The indicator offers the interesting property of being both excitation and emission rationable, thus ratiomeric measurements are possible both in excitations as emission mode. Further spectroscopic data (0.1 M Tris, pH 8.0): low [Ca²⁺], Exc.max. 362 nm, Em.max. 500 nm; high [Ca²⁺], Exc.max. 332 nm, Em.max. 500 nm

Bottomless glass bottle. Contents are inside inserted fused cone.

Intracellular, ratiomeric, fluorescent Ca²⁺/Mg²⁺ indicator with high brightness