Table 2.

Comparison of IC50 (nM) values of synthetic MC-LA and variants in relation to the purified catalytic subunits of PP1 and PP2A.

					Inhibition (IC50 nm)
Inhibitor	R	R′	R″	R‴	PP1c	PP2Ac	PP1 selectivity
MC-LA (synthetic)	H	CH(CH3)2	CH3	=CH2	0.3	0.3	1
1	H	Cyclohexyl	CH3	CH2	0.52	3.4	7
2	H	i-Propyl	Cyclohexyl	H	0.8	1.5	2
3	H	i-Propyl	CH3	H	0.8	1.5	2
4	NH3+	i-Propyl	CH3	CH2	3	9	3