Table 1. Comparison of FcεRI-bound Er-IgE phosphorescence anisotropy decay at 4°C for the HC Er-SPE-7 vs. PC Er-H1 DNP-ε-206 IgEs.

IgE	r0	r∞	Rotational correlation time, μs	n
Er-SPE-7	0.033 ± 0.006	0.045 ± 0.008	27 ± 10	11
Er-H1 DNP-ε-206	0.016 ± 0.004	0.041 ± 0.013	52 ± 13	6

The labeling concentration for each IgE shown was 25 nM. r₀, Initial anisotropy; r_∞, limiting or long-time anisotropy.