Uncaging

Introduction - Caged compounds

Caged compounds are biologically inactive substances with a photoactivatable group. Upon absorbing an appropriate photon the caged group can be cleaved and the active biological substance is released. With caged compounds it is for example possible to investigate second messengers independent of preceding signal transduction chain elements.

Several caging groups for a variety of biological substances are available. These caging groups vary in their spectral properties.

Caged substances range from ions, second messengers and amino acids to fluorescent dyes. Kits for caging carboxylic acids are also available.

Equipment

A light source with output in the UV-light range is needed. This can be a laser, mercury-lamp, UV-flash or even a monochromator. It has to be chosen whether only a part of the field of view needs to be illuminated, to control the release of the caged compound spatially, or whether the whole field of view needs to be illuminated for rapid and quantitative release of the caged compound.

Agilent offers a UV-flash and the Polychrome 5000 as light sources for uncaging.

Applications

One example for a method investigating second messengers and using caged compounds is:

• Bedner P, Niessen H, Odermatt B, Willecke K, Harz H.
  A method to determine the relative cAMP permeability of connexin channels.
  2003 Exp Cell Res. 15;291(1):25-35.

Read more about uncaging Ca²⁺ using the Polychrome or using a Photometry Setup.