word of the day: actinic

The word of the day is actinic:

Etymology:  < ancient Greek ἀκτῖν-, ἀκτίς ray (see actino- comb. form) + -ic suffix.

1. Of or relating to actinism; (of light) having the ability to cause a chemical change; having a relatively high ultraviolet content; = photogenic adj. 1.
2. Esp. of a medical condition: produced or caused by the action of light; = photogenic adj. 2. (OED)

"Photoaffinity probes need to fit the following requirements: the probe must be chemically inert in the absence of actinic light; the photophore has to be activated under mild conditions and its activation must not damage the biosystem and its components; the lifetime of the excited state of the label has to be shorter than the lifetime of a ligand-receptor or another complex under study; the activated probe has to nonspecifically react with any neighboring group, including saturated CH-chains of lipids and nonpolar amino acid residues, with production of a tight covalent bond; the photophore must not induce significant disorders in the biosystem organization; the photophore introduction into the initial substance molecule must not considerably decrease the biological activity; the probe has to contain a radionuclide with a sufficiently high specific activity or an additional label attached through an elongated linker; the probe has to be available."

 - E. L. Vodovoza, "Photoaffinity Labeling and Its Application in Structural Biology", Biochemistry (Moscow) 72:1 (2007)