Table 1.

The binding properties and uptake kinetics of the fluorescent phorbol esters

Ligandlog Po/wReceptor binding (Ki, nmol/L)
Uptake kinetics
RasGRP, 35-minPKCα, 5-minPKCδ, 5-minPKCδ, 30-minEk (min1)t1/2 (min)
PDBu (Kd)0.94 ± 0.020.30 ± 0.050.39 ± 0.004
Ligands with a green BODIPY FL fluorophore
 PE-BDFL-C22.255.7 ± 1.21.4 ± 0.13.0 ± 0.21.5 ± 0.111.6 ± 1.30.18 ± 0.0244
 PE-BDFL-C43.2312.7 ± 0.76.0 ± 0.34.8 ± 0.42.8 ± 0.216.0 ± 0.90.13 ± 0.0366
 PE-BDFL-C106.185.7 ± 0.716.0 ± 0.58.1 ± 0.42.2 ± 0.021.6 ± 2.50.0049 ± 0.00083140
 PE-BDFL-C158.6492.7 ± 3.9211 ± 17199 ± 2631.2 ± 6.3
Ligands with a red BODIPY 581/591 fluorophore
 PE-BD581-C45.4421.1 ± 0.510.8 ± 2.38.6 ± 0.81.4 ± 0.411.7 ± 0.40.0123 ± 0.000656
 PE-BD581-C108.32210 ± 2086.6 ± 4.471.0 ± 6.924.4 ± 2.2
  • NOTE: For PDBu, Kd values are shown for comparison. For uptake kinetics, E represents the equilibrium coefficient, k represents the rate of uptake, and t1/2 represents the half-life, as determined using 1 μmol/L of fluorescent ligand. Empirically determined values for Ki, E, and k are the mean ± SE for three or more experiments.