1. Epigenetics
  2. Histone Acetyltransferase
    Epigenetic Reader Domain
  3. C646


Cat. No.: HY-13823 Purity: >98.0%
Handling Instructions

C646 is a selective and competitive histone acetyltransferase p300 inhibitor with Ki of 400 nM, and is less potent for other acetyltransferases.

For research use only. We do not sell to patients.

C646 Chemical Structure

C646 Chemical Structure

CAS No. : 328968-36-1

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10 mM * 1 mL in DMSO USD 130 In-stock
Estimated Time of Arrival: December 31
10 mg USD 118 In-stock
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50 mg USD 456 In-stock
Estimated Time of Arrival: December 31
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Customer Review

Based on 13 publication(s) in Google Scholar

Top Publications Citing Use of Products

    C646 purchased from MCE. Usage Cited in: Eur J Pharmacol. 2017 Oct 5;812:206-215.

    C646 inhibits the proliferation of Cervical cancer cells and induced the accumulation of p53 protein. Protein levels of p53 and p21 are augmented by C646 in a dose-dependent manner. Whole cell lysates are analyzed with western-blot analysis.

    C646 purchased from MCE. Usage Cited in: Biochem Biophys Res Commun. 2016 Dec 2;481(1-2):90-96.

    DMKG inhibits autophagy of HSCs via acetyl-coenzyme A and EP300. Western blot analysis of LC3B, Beclin-1, a-SMA, and collagen-I expression from lysates of HSC-T6 incubated with control media, DMKG (4 mM), or Lipoic acid (5 mM) in the presence or absence of C646 (10 mM) for 12 h.

    C646 purchased from MCE. Usage Cited in: Cell Death Differ. 2018 Nov;25(11):1980-1995.

    Western blot analysis of LAMC2 expression after C646 treatment in KYSE150 and KYSE450. C646 treatment: 20μM, 12h.

    C646 purchased from MCE. Usage Cited in: Free Radic Biol Med. 2018 Aug 20;124:454-465.

    To explore whether P300 is required for NaB’s activation of Nrf2 expression and function, HG-treated endothelial cells (ECs) are co-treated with NaB, in the presence or absence of C646.
    • Biological Activity

    • Protocol

    • Purity & Documentation

    • References

    • Customer Review


    C646 is a selective and competitive histone acetyltransferase p300 inhibitor with Ki of 400 nM, and is less potent for other acetyltransferases.

    IC50 & Target

    Ki: 400 nM (histone acetyltransferase p300)

    In Vitro

    C646 is a linear competitive inhibitor of p300 versus acetyl-CoA with a Ki of 400 nM. C646 shows a noncompetitive pattern of p300 inhibition versus H4-15 peptide substrate. C646 treatment reduces histone H3 and H4 acetylation levels and abrogates TSA-induced acetylation in cells. C646 has a more potent effect on cell growth than Lys-CoA-Tat does[1]. C646 enhances mitotic catastrophe after IR and suppresses phosphorylation of CHK1 after IRin A549 cells[2]. C646 attenuates the increased acetylation of GATA1 and the increased transcriptional activity of GATA1 induced by EDAG[3].

    Molecular Weight




    CAS No.





    Room temperature in continental US; may vary elsewhere.

    Powder -20°C 3 years
      4°C 2 years
    In solvent -80°C 6 months
      -20°C 1 month
    Solvent & Solubility
    In Vitro: 

    DMSO : 16.67 mg/mL (37.43 mM; Need ultrasonic)

    Stock Solutions
    Concentration Solvent Mass 1 mg 5 mg 10 mg
    1 mM 2.2451 mL 11.2254 mL 22.4507 mL
    5 mM 0.4490 mL 2.2451 mL 4.4901 mL
    10 mM 0.2245 mL 1.1225 mL 2.2451 mL
    *Please refer to the solubility information to select the appropriate solvent.
    Kinase Assay

    Reactions are carried out at 30°C for times varying from 2 to 4 min under the following reaction conditions: 50 mM HEPES, pH 7.9, 50 mM NaCl, 0.05 mg/mL BSA, 5 mM DTT, 0.05 mM EDTA, 0.25% DMSO, 10 μM of X. laevis histone H3, and varying concentrations of C646 (0, 3, 10 μM). The reactions contains either 70 nanograms of Rtt109/Vps75, 15 nanograms of yGcn5, 300 nanograms of the SAS complex or 1 microgram of hMOZ. The amount of enzyme used in each assay is estimated by comparing Coomassie Blue staining of samples with bovine serum albumin standards, analyzed by SDS-PAGE. The mixture is allowed to equilibrate at 30°C for 10 min before the reaction is initialed with addition of a 1:1 mixture of 12C-AcCoA and 14C-AcCoA to a final concentration of 20 μM. After the appropriate time the reaction is quenched with 6 X Tris-Tricine gel loading buffer which contains 0.2mol/LTris-Cl pH 6.8, 40% v/v glycerol, 14% w/v SDS, 0.3 mol/LDTT, and 0.06% w/v Coomassie Blue. The 14C-labeled histone substrates are separated from reactants on a 16.5% Tris-Tricine SDS-PAGE gel. The rate of 14C-incorporation into histone H3 is quantified by autoradiography. All assays are in duplicate, and these generally agree within 20%.

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

    Cell Assay

    Cells are seeded in 6-well plates, incubated at 37°C for 4-10 h for attachment, and exposed (or not) to C646. After incubation for 2 h, the cells are subjected (or not) to IR and incubated for 10 days for colony formation. The cells are fixed with methanol and stained with crystal violet. Colonies of at least 50 cells are counted. The surviving fraction is normalized to the corresponding controls. The dose required to reduce the surviving fraction to 10% (D10) of the irradiated cells is calculated by using the linear-quadratic model.

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

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    C646C 646C-646Histone AcetyltransferaseAutophagyEpigenetic Reader DomainApoptosisHATsHATInhibitorinhibitorinhibit

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