Cyclotraxin B is a cyclic peptide that is a potent and specific TrkB inhibitor (antagonist) without altering BDNF binding. Cyclotraxin B noncompetitively inhibits BDNF-induced TrkB activity with IC50 of 0.30 nM. Cyclotraxin B crosses the BBB (blood-brain barrier) and has analgesic and anxiolytic behavioral effects.

Physicochemical Properties

Molecular Formula	C48H73N13O17S3
Molecular Weight	1200.36512732506
Exact Mass	1199.44
CAS #	1203586-72-4
Related CAS #	Cyclotraxin B TFA
PubChem CID	90489002
Appearance	White to off-white solid powder
LogP	-9
Hydrogen Bond Donor Count	16
Hydrogen Bond Acceptor Count	22
Rotatable Bond Count	16
Heavy Atom Count	81
Complexity	2230
Defined Atom Stereocenter Count	10
SMILES	S(C)CC[C@H]1C(NCC(N[C@H](C(N[C@@H]([C@@H](C)O)C(N[C@H](C(N[C@H](C(NCC(N[C@H](C(=O)O)CSSC[C@@H](C(N[C@@H](CC(N)=O)C(N2CCC[C@H]2C(N1)=O)=O)=O)N)=O)=O)CCC(=O)O)=O)CCCCN)=O)=O)CC1C=CC(=CC=1)O)=O)=O
InChi Key	JLBMMJHZUYBFGX-ZHTCEXBHSA-N
InChi Code	InChI=1S/C48H73N13O17S3/c1-24(62)39-46(75)58-28(6-3-4-15-49)43(72)56-29(12-13-38(67)68)41(70)52-21-37(66)55-33(48(77)78)23-81-80-22-27(50)40(69)59-32(19-35(51)64)47(76)61-16-5-7-34(61)45(74)57-30(14-17-79-2)42(71)53-20-36(65)54-31(44(73)60-39)18-25-8-10-26(63)11-9-25/h8-11,24,27-34,39,62-63H,3-7,12-23,49-50H2,1-2H3,(H2,51,64)(H,52,70)(H,53,71)(H,54,65)(H,55,66)(H,56,72)(H,57,74)(H,58,75)(H,59,69)(H,60,73)(H,67,68)(H,77,78)/t24-,27+,28+,29+,30+,31+,32+,33+,34+,39+/m1/s1
Chemical Name	(3S,6R,11R,17S,20S,23S,26S,32S,35S)-6-amino-20-(4-aminobutyl)-3-(2-amino-2-oxoethyl)-17-(2-carboxyethyl)-23-[(1R)-1-hydroxyethyl]-26-[(4-hydroxyphenyl)methyl]-32-(2-methylsulfanylethyl)-2,5,13,16,19,22,25,28,31,34-decaoxo-8,9-dithia-1,4,12,15,18,21,24,27,30,33-decazabicyclo[33.3.0]octatriacontane-11-carboxylic acid
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets

TrkB

References

[1]. Cyclotraxin-B, the first highly potent and selective TrkB inhibitor, has anxiolytic properties in mice. PLoS One. 2010 Mar 19;5(3):e9777. [2]. Cyclotraxin-B, a new TrkB antagonist, and glial blockade by propentofylline, equally prevent and reverse cold allodynia induced by BDNF or partial infraorbital nerve constriction in mice. J Pain. 2012 Jun;13(6):579-89. [3]. Systemic Delivery of a Brain-Penetrant TrkB Antagonist Reduces Cocaine Self-Administration and Normalizes TrkB Signaling in the Nucleus Accumbens and Prefrontal Cortex. J Neurosci. 2016 Aug 3;36(31):8149-59.

Solubility Data

Solubility (In Vitro)	H2O: 100 mg/mL (83.31 mM)
Solubility (In Vivo)	Solubility in Formulation 1: 100 mg/mL (83.31 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	0.8331 mL	4.1654 mL	8.3308 mL
	5 mM	0.1666 mL	0.8331 mL	1.6662 mL
	10 mM	0.0833 mL	0.4165 mL	0.8331 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.