Apamin (trifluoroacetate salt)

Apamin is an 18-amino acid peptide toxin that has been found in honey bee (A. mellifera) venom. It is an inhibitor of small conductance calcium-activated potassium (KCa2.2/SK2) channels (IC50s = 0.06-0.4 nM). It is selective for KCa2.2/SK2 channels over KCa2.1/SK1 and KCa2.3/SK3 channels (IC50s = 1-12 and 1-13 nM, respectively), as well as the intermediate-conductance calcium-activated potassium channel KCa3.1/SK4 at 1 µM but does inhibit voltage-gated potassium channel 1.3 (Kv1.3, IC50 = 13 nM). Apamin (50 µg/kg) reduces CD8+ cell infiltration into the CNS and the severity of experimental autoimmune encephalomyelitis (EAE), as well as increased peripheral blood levels of CD62L-, CD44L-, and CD44+ memory T cells in mice. It has commonly been used to determine the role of KCa/SK channels in the brain, vascular endothelium, and bladder.Formal Name: L-cysteinyl-L-asparaginyl-L-cysteinyl-L-lysyl-L-alanyl-L-prolyl-L-alpha-glutamyl-L-threonyl-L-alanyl-L-leucyl-L-cysteinyl-L-alanyl-L-arginyl-L-arginyl-L-cysteinyl-L-glutaminyl-L-glutaminyl-L-histidinamide, cyclic (1->11),(3->15)-bis(disulfide), trifluoroacetate salt. CAS Number: 24345-16-2. Synonyms: Ro 23-6721. Molecular Formula: C79H131N31O24S4 . XCF3COOH. Formula Weight: 2027.3. Purity: >95%. Formulation: (Request formulation change), A solid. Solubility: Water: 1 mg/ml. SMILES: O=C([C@]1(N(CCC1)C([C@H](C)NC([C@H](CCCCN)NC([C@@]([H])(NC([C@@H](CC(N)=O)NC([C@@](N)([H])CSSC2)=O)=O)CSSC[C@@H](C(N[C@H](C(N[C@H](C(N[C@@H](CC3=CNC=N3)C(N)=O)=O)CCC(N)=O)=O)CCC(N)=O)=O)NC([C@H](CCCNC(N)=N)NC4=O)=O)=O)=O)=O)[H])N[C@@H](CCC(O)=O)C(N[C@@H]([C@@H](C)O)C(N[C@@H](C)C(N[C@@H](CC(C)C)C(N[C@]2(C(N[C@@H](C)C(N[C@]4(CCCNC(N)=N)[H])=O)=O)[H])=O)=O)=O)=O.FC(F)(C(O)=O)F. InChi Code: InChI=1S/C79H131N31O24S4.C2HF3O2/c1-35(2)26-49-70(127)107-51-31-136-135-30-41(81)63(120)105-50(28-57(84)114)71(128)108-53(73(130)99-42(12-7-8-22-80)64(121)96-38(5)77(134)110-25-11-15-54(110)75(132)102-47(18-21-58(115)116)69(126)109-59(39(6)111)76(133)95-37(4)62(119)104-49)33-138-137-32-52(106-66(123)44(14-10-24-92-79(88)89)98-65(122)43(13-9-23-91-78(86)87)97-61(118)36(3)94-72(51)129)74(131)101-45(16-19-55(82)112)67(124)100-46(17-20-56(83)113)68(125)103-48(60(85)117)27-40-29-90-34-93-40,3-2(4,5)1(6)7/h29,34-39,41-54,59,111H,7-28,30-33,80-81H2,1-6H3,(H2,82,112)(H2,83,113)(H2,84,114)(H2,85,117)(H,90,93)(H,94,129)(H,95,133)(H,96,121)(H,97,118)(H,98,122)(H,99,130)(H,100,124)(H,101,131)(H,102,132)(H,103,125)(H,104,119)(H,105,120)(H,106,123)(H,107,127)(H,108,128)(H,109,126)(H,115,116)(H4,86,87,91)(H4,88,89,92),(H,6,7)/t36-,37-,38-,39+,41+,42-,43-,44-,45-,46-,47-,48-,49-,50+,51+,52-,53-,54-,59-,/m0./s1. InChi Key: GUBJIBRYPCCYMV-ZKPRYNSTSA-N.