New fluorescent reagents specific for Ca(2+)-binding proteins.

Ca(2+) carries information pivotal to cell life and death via its interactions with specific binding sites in a protein. We previously developed a novel photoreactive reagent, azido ruthenium (AzRu), which strongly inhibits Ca(2+)-dependent activities. Here, we synthesized new fluorescent ruthenium-based reagents containing FITC or EITC, FITC-Ru and EITC-Ru.