Calcium ionophore A23187 is a carboxylic acid antibiotic with weak in vitro activity against Gram-positive organisms. It increases the potential of divalent ions to cross biological membranes, thus it acts as an ionophore. Calcium ionophore A23187 specifically forms stable 2:1 complex with divalent cations, rendering these ions soluble in ordinary organic solvents. Since calcium ionophore A23187 is commonly used to increase intracellular Ca2+ levels in intact cells, it acts as an uncoupler of oxidative phosphorylation and an inhibitor of mitochondrial adenosine triphosphatase (ATPase) activity. Calcium Ionophore A23187 is a potent inducer of phosphorylation of Toxoplasma eukaryotic initiation factor-2α (eIF2α). It also induces apoptosis in mouse lymphoma cell line (S49)7 but also has been shown to block apoptosis in other systems, such as when interleukin-3 (IL-3) is withdrawn from IL-3-dependent cells. Calcium ionophore A23187 is widely used as artificial activating substances for human oocytes.

with heating or sonication. Solutions are stable for at least 3 months at -20 °C when protected from light and water contamination.

with heating. Solutions are stable for at least 3 months at -20 °C when protected from light and water contamination.

Calcium ionophore A23187 has been used:

• as an endoplasmic reticulum (ER) stress inducer to study its effect on the expression of the toxoplasma unfolded protein response (UPR) genes
• for the induction of the acrosome reaction
• in skeletal muscle sarcoplasmic reticulum Ca²⁺ ATPase (SERCA) activity assay

Ionophore highly selective for Ca²⁺. Potentiates responses to NMDA but not quisqualate. In cell culture, stimulates nitric oxide production by calmodulin-dependent constitutive nitric oxide synthase.