Ionomycin are ionophores that form complexes with divalent metal cations; the complexes are lipid-soluble and hence, they are permeable cellular membranes. It’s divalent cation selectivity order as determined by ion competition experiments was found to be Ca2+ > Mg2+≫ Sr2+ = Ba2+, where the binding of strontium and barium by the antibiotic is insignificant. It is usually used in research to improve and to understand the permeability of biological membranes to Ca2+ into and out of cells. It is a new antibiotic isolated from the bacterium Streptomyces conglobatus. Ionomycin can be used to foster intracellular calcium levels activating cell death via apoptosis and autophagy. The calcium salt of the antibiotics has a molecular weight of 746 g/mol and structural formula of C41H70O9Ca. It is categorized as a polyether antibiotic. It is a colorless crystalline substance with melting point of 205 – 206 ᵒC. it is soluble in hexane, chloroform and acetone, slightly soluble in methanol and ethanol but insoluble in water, acid and base.
The antibiotics is distinguishable from other polyether antibiotics by its ultraviolet absorption at 300nm. It is specifically active against Gram positive bacteria. The cell of these bacteria is enclosed by the peptidoglycan layer that is porous and allows small molecules to pass through, the lipophilic ionomycin can therefore penetrate the cytoplasmic membrane, where it rapidly dissolves into the membrane. Gram negative bacteria on the contrary doesn’t show any significant activity against the antibiotics unless the lipopolysaccharide outer membrane is removed.
For research purpose, Fermentek manufacture commercial Ionomycin calcium salt and Ionomycin free salt in bulk with high purity. The antibiotics can be used to study the influence of calcium flux on endoplasmic reticulum (ER) stress, mitochondrial stress and intrinsic apoptosis process. Also, it can be used to intensify the intracellular production of the cytokines, interferon, perforin, IL-2, and IL-4 usually in conjunction with PMA. The calcium ionophore has been used by some researchers to activate oocyte in severe male infertility, mechanism of the airway hyperresponsiveness (AHR) induced by this antibiotic is also a new area of research on Ionomycin calcium salt.