| Size | Price | Stock | Qty |
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| 1mg |
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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
PKI (14-24) amide TFA targets the catalytic subunit of protein kinase A (PKA), also known as PKA Calpha, Cbeta, and Cgamma. It binds to the active site of the catalytic subunit with high affinity (Ki in the low nanomolar range, typically 1-10 nM), acting as a competitive inhibitor with respect to protein/peptide substrates. The peptide contains the pseudosubstrate sequence (RRRNAI) that mimics the PKA consensus phosphorylation motif (RRXS/T), with an alanine residue replacing the serine/threonine that would normally be phosphorylated. This alanine substitution renders the peptide a substrate competitor that blocks access of physiological substrates to the active site. It does not bind to the regulatory subunits of PKA nor to other AGC family kinases with high affinity.
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| ln Vitro |
Cyclic AMP-induced saponin-permeable cellular amylase release is not inhibited by PKI (14–24)amide TFA [2].
In vitro, PKI (14-24) amide TFA potently inhibits PKA activity in cell lysates. In PKA kinase assays using purified PKA catalytic subunit and a peptide substrate (e.g., kemptide, LRRASLG), the peptide shows an IC50 typically between 1-50 nM. In cell-free assays, it strongly inhibits cAMP-dependent protein kinase activity in cell homogenates, as measured by the phosphorylation of various synthetic substrates (e.g., histone H1, or specific PKA peptide substrates). The inhibition is competitive with substrate but non-competitive with ATP. The peptide also inhibits PKA activity in neuronal tissue extracts. No activity against other protein kinases (e.g., PKC, PKB/Akt, CaMKII) is observed at concentrations up to 10 uM. |
| ln Vivo |
PKI (14-24) amide TFA is used in vivo as a pharmacological inhibitor of PKA in animal models to investigate the role of PKA in various physiological and pathological processes. It has been administered by intracerebroventricular (ICV) injection into the brain, by intrathecal (IT) injection into the spinal cord, and by direct tissue microinjection. For example, in a rat model of neuropathic pain, intrathecal injection of PKI (14-24) amide (0.1-10 ug) reversed PKA-mediated hypersensitivity, reducing mechanical allodynia and thermal hyperalgesia. In mouse models of memory, intrahippocampal infusion of 10-50 uM PKI (14-24) amide impaired long-term potentiation (LTP) and memory consolidation. The peptide does not readily cross the blood-brain barrier and must be administered directly into the CNS or into tissues via injection. It is not typically administered systemically due to rapid degradation.
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| Enzyme Assay |
A standard protocol for PKA inhibition in a cell-free kinase assay: Prepare a reaction mixture containing 20 mM Tris-HCl pH 7.5, 10 mM MgCl2, 0.2 mM ATP, 0.1 mg/mL BSA, 50 uM kemptide substrate, and 0.5 nM purified PKA catalytic subunit. Add serial dilutions of PKI (14-24) amide TFA (0.1-1000 nM) and pre-incubate for 5 minutes at 30degC. Initiate the reaction by adding ATP. After 15 minutes, stop the reaction by adding phosphoric acid to 0.5%. Spot 20 uL of the reaction onto P81 phosphocellulose paper, wash 3 times with 0.75% phosphoric acid, dry, and quantify incorporated radioactivity by scintillation counting. Non-radioactive alternatives: ADP-Glo™ or Transcreener® ADP fluorescence assays. IC50 is determined by nonlinear regression.
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| Cell Assay |
For cell-based assays to inhibit PKA activity: Neuronal cell lines (e.g., PC12, SH-SY5Y, primary cortical neurons) or HEK293 cells are seeded in 6-well plates (1×10⁶ cells/well) and grown to 80% confluence. To deliver the peptide into cells, use a cell-permeabilization agent (e.g., Streptolysin O or digitonin) or physically load the peptide by microinjection for large cells. Alternatively, synthetic PKI amide peptides can be conjugated to cell-penetrating peptides (e.g., TAT, penetratin) for efficient uptake. For cell lysate experiments: Cells are treated with the peptide (0.1-10 uM) for 1-4 hours or pre-incubated with the peptide in hypotonic lysis buffer prior to PKA activation. To measure PKA activity in cell lysates, the cells are stimulated with forskolin (10 uM) or IBMX (100 uM) to increase cAMP levels, or directly with the PKA activator Sp-cAMPS (100 uM). After 10-15 minutes, cells are lysed, and PKA activity is measured using a commercial PKA kinase activity kit (e.g., Promega PepTag, SignalChem PKA assay). Western blotting for p-CREB Ser133 is used as a readout of PKA activity in intact cells if the peptide is successfully delivered. The amide form of PKI (14-24) is resistant to carboxypeptidase degradation but may still be sensitive to aminopeptidase and other proteases; protease inhibitors can be included in cell lysis buffer to preserve peptide activity.
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| Animal Protocol |
For in vivo studies: For intrathecal injection in rats, male Sprague-Dawley rats (250-300 g) are anesthetized with isoflurane and placed in a stereotaxic apparatus. A 30-gauge needle attached to a 25 uL Hamilton syringe is inserted into the subarachnoid space between the L5 and L6 vertebrae. PKI (14-24) amide TFA is dissolved in sterile artificial CSF (aCSF) or PBS, pH 7.4, at concentrations ranging from 0.1-100 uM (typically 10 uM, 5-10 uL volume). The peptide is injected over 1-2 minutes. For intrahippocampal injection in mice (C57BL/6, 8-12 weeks), bilateral guide cannulae are implanted into the dorsal hippocampus (coordinates: AP -2.0 mm, ML +/-1.5 mm, DV -1.5 mm from bregma). After 5-7 days of recovery, animals are briefly anesthetized, and injection needles (extending 1 mm beyond guide) are inserted. PKI (14-24) amide is infused at a rate of 0.25 uL/min for a total volume of 0.5-1.0 uL (0.5-5 ug/side). For memory studies, the peptide is infused immediately after training in a fear conditioning or Morris water maze paradigm. After behavioral testing, correct placement is verified by histology. In pain studies, mechanical allodynia is measured using von Frey filaments, and thermal hyperalgesia is assessed using the Hargreaves test before and after peptide injection.
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| ADME/Pharmacokinetics |
No formal pharmacokinetic data are available for PKI (14-24) amide TFA. The peptide is rapidly degraded by proteases in serum and tissue homogenates (half-life in serum is typically <30 minutes). It does not cross the blood-brain barrier (BBB) in significant amounts due to its size (~1200-1400 Da) and polarity. Therefore, direct CNS administration (ICV, intrathecal, or brain infusion) is required for central nervous system studies. For systemic administration, the peptide would be rapidly cleared by the kidneys (via glomerular filtration) and degraded by proteolytic enzymes in the blood and tissues. The TFA salt form enhances peptide solubility in aqueous buffers (PBS, water). Peptide stock solutions (1-10 mM) are typically stored in aliquots at -20degC or -80degC to avoid freeze-thaw cycles. The peptide is stable for months when stored lyophilized at -20degC.
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| Toxicity/Toxicokinetics |
PKI (14-24) amide TFA has low toxicity at the doses used in research (typically ug to low mg/kg range). In mice, intrathecal doses up to 50 ug (approximately 2.5 mg/kg) do not cause overt behavioral changes or motor impairment. Intrahippocampal injection of 10 uM (5 ug/side) does not cause neuronal cell death as assessed by NeuN staining. No systemic acute toxicity data are available. At very high concentrations (100 uM, 50 ug/side), mild neuroinflammation (microglial activation) may occur, but this is not consistently reported. The peptide is not mutagenic or carcinogenic. Standard laboratory precautions (gloves, lab coat, eye protection) should be used when handling peptide powders. Avoid aerosolization. The peptide is for research use only and should not be administered to humans.
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| References |
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| Additional Infomation |
PKI (14-24) amide TFA is not a drug and has no clinical trial or regulatory approval status. It is a research peptide exclusively for scientific use as a PKA inhibitor. It is a shorter, more stable derivative of the full-length PKI (5-24) peptide that was originally isolated from rabbit skeletal muscle. This peptide is widely used as a standard tool to validate PKA involvement in signal transduction pathways. The pseudosubstrate inhibition mechanism is also exploited in designing specific inhibitors for other protein kinases by substituting the key alanine residue. While PKI amide itself is not a therapeutic candidate, understanding its mechanism has contributed to drug discovery efforts targeting PKA in diseases such as heart failure, cancer, inflammatory disorders, and neurological diseases. The peptide is commercially available from numerous vendors for research purposes.
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| Molecular Formula |
C51H87F3N24O17
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| Molecular Weight |
1365.38
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| Exact Mass |
1364.663
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| CAS # |
1293946-39-0
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| Related CAS # |
PKI (14-24)amide;100853-61-0
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| PubChem CID |
71311694
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| Appearance |
White to off-white solid powder
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| Hydrogen Bond Donor Count |
23
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| Hydrogen Bond Acceptor Count |
25
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| Rotatable Bond Count |
42
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| Heavy Atom Count |
95
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| Complexity |
2590
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| Defined Atom Stereocenter Count |
11
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| SMILES |
[C@H](C(=O)N[C@H](C(=O)N)CC(=O)O)(NC(=O)[C@H]([C@@H](C)CC)NC(=O)[C@H](C)NC(=O)[C@H](CC(=O)N)NC(=O)[C@H](CCCNC(N)=N)NC(=O)[C@H](CCCNC(N)=N)NC(=O)CNC(=O)[C@H]([C@H](O)C)NC(=O)[C@@H](NC(=O)CN)CCCNC(N)=N)CC1NC=NC=1.C(F)(F)(F)C(=O)O
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| InChi Key |
WHXDJOUKXDRBLV-IQFKIXDSSA-N
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| InChi Code |
InChI=1S/C49H86N24O15.C2HF3O2/c1-5-22(2)36(46(88)71-30(15-25-19-59-21-64-25)44(86)69-29(38(52)80)17-35(78)79)72-39(81)23(3)65-43(85)31(16-32(51)75)70-41(83)28(11-8-14-62-49(57)58)68-40(82)26(9-6-12-60-47(53)54)67-34(77)20-63-45(87)37(24(4)74)73-42(84)27(66-33(76)18-50)10-7-13-61-48(55)56;3-2(4,5)1(6)7/h19,21-24,26-31,36-37,74H,5-18,20,50H2,1-4H3,(H2,51,75)(H2,52,80)(H,59,64)(H,63,87)(H,65,85)(H,66,76)(H,67,77)(H,68,82)(H,69,86)(H,70,83)(H,71,88)(H,72,81)(H,73,84)(H,78,79)(H4,53,54,60)(H4,55,56,61)(H4,57,58,62);(H,6,7)/t22-,23-,24+,26-,27-,28-,29-,30-,31-,36-,37-;/m0./s1
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| Chemical Name |
(3S)-4-amino-3-[[(2S)-2-[[(2S,3S)-2-[[(2S)-2-[[(2S)-4-amino-2-[[(2S)-2-[[(2S)-2-[[2-[[(2S,3R)-2-[[(2S)-2-[(2-aminoacetyl)amino]-5-(diaminomethylideneamino)pentanoyl]amino]-3-hydroxybutanoyl]amino]acetyl]amino]-5-(diaminomethylideneamino)pentanoyl]amino]-5-(diaminomethylideneamino)pentanoyl]amino]-4-oxobutanoyl]amino]propanoyl]amino]-3-methylpentanoyl]amino]-3-(1H-imidazol-5-yl)propanoyl]amino]-4-oxobutanoic acid;2,2,2-trifluoroacetic acid
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| HS Tariff Code |
2934.99.9001
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| 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 and light. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
H2O: 100 mg/mL (73.24 mM)
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.7324 mL | 3.6620 mL | 7.3240 mL | |
| 5 mM | 0.1465 mL | 0.7324 mL | 1.4648 mL | |
| 10 mM | 0.0732 mL | 0.3662 mL | 0.7324 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.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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