1.14.99.21 (1E)-2-methyl-4-(2-methylphenyl)but-1-en-1-yl formate IC50: 0.460 mM 56662 1.14.99.21 (1E)-2-methyl-4-phenylbut-1-en-1-yl formate IC50: 6.96 mM 56663 1.14.99.21 oxyluciferin IC50: 0.436 mM 3658