First-order rate constants of decay (k, s−1) and fraction activities (a) of visual pigment intermediates in salamander red cones
| MII | MII-P | M-P-Arr | Ops | kPDE s−1 | aRH | |||||
| kP s−1 | aM* | kA s−1 | aMP | kD s−1 | aMA | kR s−1 | aOps | |||
| 11-cis | 5 | 1 | 1 | 0.002 | 0.21 | 2.7 × 10−5 | 2 × 10−2 | 4 × 10−6 | 3.5 | nd |
| 9-DM | 5 | 1 | 1.05 | 0.004 | 0.042 | 1.1 × 10−4 | 2 × 10−2 | 4 × 10−6 | 3.5 | nd |
| MII | MII-P | M-P-Arr | Ops | kPDE s−1 | aRH | |||||
| kP s−1 | aM* | kA s−1 | aMP | kD s−1 | aMA | kR s−1 | aOps | |||
| 11-cis | 5 | 1 | 1 | 0.002 | 0.21 | 2.7 × 10−5 | 2 × 10−2 | 4 × 10−6 | 3.5 | nd |
| 9-DM | 5 | 1 | 1.05 | 0.004 | 0.042 | 1.1 × 10−4 | 2 × 10−2 | 4 × 10−6 | 3.5 | nd |
kP and kE are determined from fitting the full model of phototransduction to nonsaturated flash responses; kD values are obtained by single-exponential fitting to Meta decay in Fig. 3; kA, aMP, aMA, and aOps from fitting the kinetic scheme above to Tsat versus bleach data, using previously found kP, kE, and kD. These results, together with Fig. 7, suggest that, in addition to slower decay, the residual activity of 9-demethyl metaproducts (aMP and aMA) is substantially higher than that of 11-cis pigment. nd, not determined.