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Ionomycin (free acid).svg
IUPAC name
(4R,6S,8S,10Z,12R,14R,16E,18R,19R,20S,21S)-19,21-Dihydroxy-22-{(2S,2′R,5S,5′S)-5′-[(1R)-1-hydroxyethyl]-2,5′-dimethyloctahydro-2,2′-bifuran-5-yl}-4,6,8,12,14,18,20-heptamethyl-11-oxido-9-oxodocosa-10,16-dienoic acid
3D model (JSmol)
ECHA InfoCard 100.121.228 Edit this at Wikidata
  • InChI=1S/C41H72O9/c1-25(21-29(5)34(43)24-35(44)30(6)22-27(3)20-26(2)14-15-38(46)47)12-11-13-28(4)39(48)31(7)36(45)23-33-16-18-41(10,49-33)37-17-19-40(9,50-37)32(8)42/h11,13,24-33,36-37,39,42-43,45,48H,12,14-23H2,1-10H3,(H,46,47)/b13-11+,34-24-/t25-,26-,27+,28-,29-,30+,31+,32-,33+,36+,37-,39-,40+,41+/m1/s1 ☒N
  • InChI=1/C41H72O9/c1-25(21-29(5)34(43)24-35(44)30(6)22-27(3)20-26(2)14-15-38(46)47)12-11-13-28(4)39(48)31(7)36(45)23-33-16-18-41(10,49-33)37-17-19-40(9,50-37)32(8)42/h11,13,24-33,36-37,39,42-43,45,48H,12,14-23H2,1-10H3,(H,46,47)/b13-11+,34-24-/t25-,26-,27+,28-,29-,30+,31+,32-,33+,36+,37-,39-,40+,41+/m1/s1
  • C[C@H](CCC(=O)O)C[C@H](C)C[C@H](C)C(=O)/C=C(/[C@H](C)C[C@H](C)C/C=C/[C@@H](C)[C@H]([C@@H](C)[C@H](C[C@@H]1CC[C@@](O1)(C)[C@H]2CC[C@@](O2)(C)[C@@H](C)O)O)O)\O
Molar mass 709.0050 g/mol
Solubility insoluble in water, soluble in fats, DMSO,[1] heptane and hexane[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Ionomycin is an ionophore and an antibiotic that binds calcium ions (Ca2+) in a ratio 1:1. It is produced by the bacterium Streptomyces conglobatus.[3] It binds also other divalent cations like magnesium and cadmium, but binds Ca2+ preferably.[1][2]

It has 14 chiral centers. Its β-diketone and carboxylic acid group form a chelate with calcium.[3]

It was extracted in 1978 and the complete structure was elucidated in 1979.[2][3]

It is used in research to raise the intracellular calcium level (Ca2+) and as a research tool to understand Ca2+ transport across biological membranes.[3]

Ionomycin is often sold as a free acid, or as a Ca2+ salt. Both are insoluble in water, but soluble in fats and DMSO. Because of their fat solubility, they bind to proteins like albumin, which may interfere with their use in studies involving blood.[1]


  1. ^ a b c Kao J, et al. (2010). "Practical aspects of measuring intracellular calcium signals with fluorescent indicators". Methods in Cell Biology. 99: 113–152. doi:10.1016/B978-0-12-374841-6.00005-0. ISBN 9780123748416. ISSN 0091-679X. PMID 21035685.
  2. ^ a b c Toeplitz BK, et al. (1979). "Structure of ionomycin - a novel diacidic polyether antibiotic having high affinity for calcium ions". Journal of the American Chemical Society. 101 (12): 3344–3353. doi:10.1021/ja00506a035. ISSN 0002-7863.
  3. ^ a b c d Lautens M, et al. (2002). "Total synthesis of ionomycin using ring-opening strategies". Organic Letters. 4 (11): 1879–1882. doi:10.1021/ol025872f. ISSN 1523-7060. PMID 12027637.