Table 1 PLpro inhibition and SARS-CoV-2 antiviral activity

From: Potent and selective covalent inhibition of the papain-like protease from SARS-CoV-2

Compound

R1a

Electrophile

IC50 (μM)b

Time dep.

kinact/KI (M−1 s−1)

EC50 (μM)c

CC50  < 30 μM

GRL0617

NH2

NA

1.2

No

NA

ND

ND

3

H

NA

>100

No

NA

ND

ND

5

H

NA

24

No

NA

ND

ND

7

H

Fumarate ester

0.094

Yes

9,600

1.1

No

8

NHAc

Fumarate ester

0.230

Yes

9,000

No CPE

No

9

H

Chloroacetamide

5.4

Yes

110

34

No

10

NHAc

Chloroacetamide

4.4

Yes

140

No CPE

No

11

H

Cyanoacetamide

8.0

No

ND

No CPE

No

12

H

Propiolamide

0.098

Yes

4,100

No CPE

Yes

13

H

α-cyanoacrylamide

>200

No

ND

No CPE

Yes

14

H

NA

100

ND

NA

No CPE

No

15

NHAc

NA

6.2

ND

NA

No CPE

No

  1. NA not applicable, ND not determined.
  2. aStructures are shown in Fig. 4.
  3. bMeasurement after 30-min incubation. Purified PLpro with Z-RLRGG-AMC substrate.
  4. cCytopathic effect in SARS-CoV-2-infected Vero E6 cells. EC50 for remdesivir = 0.74 μM.