Table 2. Properties of calcium cages.
| Ca2+ Kd (nMa) | Product Kd (mM) | ΔKd | Φ | ε (M–1 cm–1) | Φ × ε | Rate calcium release (s–1) | 2PCS (GM) | |
|---|---|---|---|---|---|---|---|---|
| NDBF-EGTA | 100 | 2.0 | 20,000 | 0.7 | 18,400 | 12,880 | 20,000 | 0.6 |
| DMNPE-4 | 48 | 2.0 | 42,000 | 0.09 | 5,120 | 461 | 45,000 | 0.01 |
| NP-EGTA | 80 | 1.0 | 12,500 | 0.23 | 975 | 224 | 68,000 | 0.001 |
| DM-nitrophen | 5 | 3.0 | 60,0000 | 0.18 | 4,300 | 774 | 38,000 | 0.01 |
| nitr-5 | 145 | 0.0063 | 54 | 0.012 | 5,500 | 66 | 2,500b | NDc |
| azid-1 | 230 | 0.12 | 520 | 1.0 | 33,000 | 33,000 | 500 | 1 |
a
Measured at pH 7.2.
b
Given is the rate of appearance of organic photo product; Ca2* is probably released at the same rate.
c
This value has not been measured, but is probably 0.01 by analogy with DM-nitrophen. ε, extinction coefficient; Φ, quantum yield. 2PCS, two-photon cross-section. ND, not determined.