TABLE 3

Binding properties of PTH-1R mutated at residue Leu41 compared with wild type PTH-1R

Values represent mean pIC50 values ± S.E. for three independent competition binding assays using four different unlabeled ligands with 125I-rPTH(1-34) as the tracer. The values are compared using d2 or d3, which represent the -fold change in mean IC50 values, where d2 compares Phe23-PTH(1-34) relative to PTH(1-34) and d3 compares PTHrP(1-36) relative to Trp23-PTHrP(1-36).

PTH(1-34) Phe23-PTH(1-34) d2 PTHrP(1-36) Trp23-PTHrP(1-36) d3
PTH-1R 8.02 ± 0.17 6.99 ± 0.21 11 6.81 ± 0.29 7.65 ± 0.15 7
L41V 8.40 ± 0.18 6.38 ± 0.31 104 5.43 ± 0.02 7.96 ± 0.23 341
L41A 8.09 ± 0.12 5.24 ± 0.23 705 <5 7.07 ± 0.06 >100
L41I 7.91 ± 0.23 7.23 ± 0.20 5 7.12 ± 0.13 7.79 ± 0.04 5
L41M 8.03 ± 0.06 6.57 ± 0.24 29 6.54 ± 0.30 7.21 ± 0.13 5