Table 6. BCAT1 and BCAT2 Activities and BCAA Measurement in U-87 MG and MDA-MB-231 Cell Lines for Inhibitors 35 and 36 and Their Respective Atropisomers a and b^a.

			BCAA IC50
compd	BCAT1 IC50	BCAT2 IC50	U-87 MG cell line	MDA-MB-231 cell line
35	70 nM	270 nM	5 μM	5 μM
35a	90 nM	290 nM	2.7 μM	780 nM
35b	3.5 μM	5.5 μM	n.a.	4.7 μM
36(43)	186 nM	1.2 μM	1.8 μM	1 μM
36a	31 nM	153 nM	358 nM	874 nM
36b	2.3 μM	2.7 μM	2 μM	n.a.

^an.a.: data not available. IC₅₀ values given are arithmetic mean values over at least two independent IC₅₀ determinations. For comparison: reference compound A (Figure 1) showed a 5.3 μM IC₅₀ in the U-87 MG cell line and a 564 nM IC₅₀ value in the MDA-MB-231 cell line.