Fig. 2.

2-phenylethylamine is a predator odor in bobcat urine. (A) Bobcat urine was fractionated by silica gel chromatography, and fractions were analyzed for the presence of TAAR4 activator with the reporter gene assay (triplicates ± SD). (B) An ion with the same mass and fragmentation pattern of 2-phenylethylamine was observed in a bobcat urine active fraction. (C) Commercial 2-phenylethylamine, but not benzylamine, activated TAAR4 (triplicates ± SD). (D) 2-phenylethylamine (10 μM) activated TAAR4 but did not similarly activate other olfactory TAARs with identified agonists.