Merck, I0634-5MG, Ionomycin calcium salt from Streptomyces conglobatus

General description
Calcium Ionomycin is a polyether antibiotic made by Streptomyces conglobatus. It can remove Ca²⁺ and divalent cations from an aqueous into an organic phase. Ionomycin enhances the influx of Ca²⁺ by triggering store-regulated cation entry rather than acting directly on the plasma membrane. It can induce apoptosis, potentially by activating a hidden enzyme that responds to calcium. Since calcium salt of ionomycin serves as a highly efficient transporter of Ca²⁺, it offers substantial benefits for studying the transport of Ca²⁺ across biological membranes. Ionomycin is employed to balance intracellular and extracellular calcium ion concentrations for in situ calibrations of fluorescent indicators.

Additionally, it is a narrow spectrum antibiotic effective against Gram-positive bacteria, obtained in pure form from the fermentation broths of Streptomyces conglobatus. It is unique amongst known polyether antibiotics due to its exceptional UV absorption maximum at 300 nm and its high affinity for calcium ions.
Application
Ionomycin calcium salt from Streptomyces conglobatus has been used as a media supplement to culture:

peripheral blood mononuclear cells (PBMCs) for immunologic assessment
oocytes for parthenogenetic activation
T cell subsets for the detection of intracellular cytokines, carboxyfluorescein diacetate succinimidyl ester (CFSE) proliferation assay, and antigen-specific suppressive function assay
in combination with phorbol12-myristate 13-acetate (PMA) to stimulate T-cell activation in various cells
as sperm capacitation medium supplement to study its impact on in vitro fertilization and increasing the efficiency of bovine embryo development
as a positive control for the detection of intracellular Ca²⁺ in adipose-derived stem cells (ASCs)(4)

Biochem/physiol Actions
Ca²⁺ ionophore that is more effective than A23187 as a mobile ion carrier for Ca²⁺.
Ca²⁺ ionophore that is more effective than A23187 as a mobile ion carrier for Ca²⁺; non-fluorescent; used to study Ca²⁺ transport across biological membranes; induces apoptotic degeneration of embryonic cortical neurons.
Ionomycin is an ionophore, widely used for validation and calibration of calcium analysis.
Preparation Note
Store ionomycin in powder form desiccated and protected from light at 2-8 °C. Under these conditions the product is stable for 3 years. Store stock solutions in ethanol or DMSO at -20 °C, protected from light. Under these conditions the stock solutions are stable for several months. For short term use (up to 6 weeks) the stock solutions maybe stored at 2-8 °C protected from light.
Other Notes
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