Table 1. HAV proteinase 3C dimerization and proteolytic activity.

NA, not applicable. C172A and C24S/C172A mutants are proteolytically inactive due to the active-site mutation.

		Freshly prepared 3C†		Stored 3C‡
C3	DTT*	Activity (%)	Monomer (%)	Activity (%)	Monomer (%)
Wild-type	−	100	90	5	50
	+	100	100	70	100
C24S	−	100	100	80	100
	+	100	100	100	100
C172A	−	NA	70	NA	1
	+	NA	90	NA	100
C24S/C172A	−	NA	100	NA	100

* 6 mM DTT was present or absent in the microassay.

† After purification in DTT-containing buffer, the proteins were directly subjected to the microassay or SDS/PAGE.

‡ Prior to the activity assay or SDS/PAGE, the proteins were transferred to DTT-free buffer and stored for approximately 10 days at 4 °C.