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Cat. No.: HY-100721 Purity: 99.96%
Handling Instructions

GC376 is a 3CLpro inhibitor; inhibits the replication of viruses TGEV, FIPV and PTV with IC50 values of 0.15, 0.2 and 0.15 μM.

For research use only. We do not sell to patients.
GC376 Chemical Structure

GC376 Chemical Structure

CAS No. : 1416992-39-6

Size Price Stock Quantity
10 mM * 1 mL in DMSO USD 603 In-stock
1 mg USD 180 In-stock
5 mg USD 540 In-stock
10 mg USD 780 In-stock
25 mg USD 1560 In-stock
50 mg USD 2520 In-stock
100 mg   Get quote  
200 mg   Get quote  

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Customer Review

Other Forms of GC376:

  • Biological Activity

  • Protocol

  • Technical Information

  • Purity & Documentation

  • References


GC376 is a 3CLpro inhibitor; inhibits the replication of viruses TGEV, FIPV and PTV with IC50 values of 0.15, 0.2 and 0.15 μM.

IC50 & Target

IC50: 0.15 μM (TGEV), 0.2 μM (FIPV), 0.15 μM (PTV), 0.15 μM (229E), 1.1 μM (MHV), 5.3 μM (MNV-1), 0.6 μM (BCV)[1]

In Vitro

GC376 covalently binds to Cys 139, Cys 147, and Cys 144 of NV 3CLpro, PV 3Cpro, and TGEV 3CLpro, respectively. GC376 is significantly effective against caliciviruses (NV and MNV-1), coronaviruses (TGEV, FIPV, MHV, 229E, and BCV), and picornaviruses (HRVs 18, 51, and 68, EV71, and PTV), with nanomolar or low micromolar IC50s, except for FCV and HAV. Interestingly, FCV is less sensitive to GC376, with IC50 of 35 μM. GC376 shows no or weak effectiveness against the replication of HAV in cells[1]. Proteases from NV, MD145 or MNV-1 are inhibited by GC376 with a similar potency. The IC50 values of GC376 against 3CLpro from NV, MD145, and MNV-1 are comparable among tested viruses[2]. GC376 effectively inhibits the replication of NPI52-resistant viruses in cell culture as wild-type viruses, indicating that the mutation does not confer cross-resistance to GC376[3].

In Vivo

GC376 exhibits favorable bioavailability and safety in cats. GC376 is rapidly absorbed after s.c. administration and the peak plasma level is reached within 2 hr after injection. The mean plasma drug concentrations remains above the 50% effective concentration (EC50) value of the aldehyde form of GC376 (8 ng/mL) for 18 hrs post injection. Virus infected cats shows improvement in attitude and resolution of fever. The profound absolute lymphopenia observed in all cats prior to antiviral treatment also returns to normal before the next blood testing one week later[3]. Nineteen of 20 cats treated with GC376 regain outward health within 2 weeks of initial treatment. However, disease signs recur 1-7 weeks after primary treatment and relapses and new cases are ultimately treated for a minimum of 12 weeks[4].

Preparing Stock Solutions
Concentration Volume Mass 1 mg 5 mg 10 mg
1 mM 1.9703 mL 9.8516 mL 19.7033 mL
5 mM 0.3941 mL 1.9703 mL 3.9407 mL
10 mM 0.1970 mL 0.9852 mL 1.9703 mL
Please refer to the solubility information to select the appropriate solvent.
Kinase Assay

The stock solution (10 mM) of GC376 is prepared in DMSO and further diluted in assay buffer. The final concentrations of DMSO in the assay did not exceed 1.5% (vol/vol). The 3CLpro from NV, MD145 or MNV-1 are incubated with various concentrations (0.01 to 50 µM) of GC376 in 25 µL of assay buffer for 30 min at 37 °C. Following incubation, 25 µL of assay buffer containing substrate is added, and the mixtures are incubated in a 96-well black plate at 37 °C for 60 min. The fluorescence signals are detected using an excitation and emission wavelength of 490 and 520 nm on a fluorescence microplate reader. The RFU are calculated for each well, and the dose-dependent FRET inhibition curves are fitted with variable slope (four parameters) using GraphPad Prism software in order to determine the IC50 values of GC376[2]. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Animal Administration

GC376 is formulated at a concentration of 53 mg/mL in 10% ethanol and 90% polyethylene glycol 400[4].

Twenty cats from 3.3-82 months of age (mean 10.4 months) with various forms of feline infectious peritonitis are accepted into a field trial. Fourteen cats presented with wet or dry-to-wet FIP and six cats presented with dry feline infectious peritonitis. GC376 is administered subcutaneously every 12 h at a dose of 15 mg/kg. Cats with neurologic signs are excluded from the study. Responses to treatment are monitored[4]. MCE has not independently confirmed the accuracy of these methods. They are for reference only.

Molecular Weight







O=C(N[[email protected]@H](CC(C)C)C(N[[email protected]@](C(S([O-])(=O)=O)O)([H])CC1C(NCC1)=O)=O)OCC2=CC=CC=C2.[Na+]


4°C, stored under nitrogen


Room temperature in continental US; may vary elsewhere

Solvent & Solubility

DMSO; In Vivo: GC376 is dissolved in 10% ethanol and 90% PEG-400.

* "<1 mg/mL" means slightly soluble or insoluble. "≥" means soluble, but saturation unknown.

Purity: 99.96%

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