Table 1.
Kinetics of Recombinant At2g23510 on Different Acyl Donors and Acceptors
| Relative activity (%)a | kcat (s−1) | Km (μM) | |
|---|---|---|---|
| Forward reaction | |||
| Acyl donorb | |||
| Sinapoyl-CoA | 100 | 5.1 ± 0.8 | 8.3 ± 1.1 |
| Coumaroyl-CoA | NDc | ||
| Caffeoyl-CoA | ND | ||
| Feruloyl-CoA | ND | ||
| Acyl acceptord | |||
| Spermidine | 100 | 5.6 ± 0.8 | 37.4 ± 5.3 |
| Putrescine | 4.7 | 0.3 ± 0.1 | 236.9 ± 32.1 |
| Cadaverine | ND | ||
| Norspermidine | ND | ||
| Spermine | ND | ||
| Homospermidine | ND | ||
| Agmatine | ND | ||
| Tyramine | ND | ||
| Reverse reaction | |||
| Disinapoyl spermidinee | 37.8 ± 7.9 | 34.6 ± 6.5 | |
| CoAf | 39.6 ± 8.2 | 83.6 ± 14.7 |
Specific activities were determined under the conditions described in Methods. For forward reactions, acyl donors and acceptors were used at final concentrations of 60 and 200 μM (400 μM for putrescine), respectively, when determining the Km for the other substrate types. The specific activity with sinapoyl-CoA and spermidine (83.7 nkat mg−1) was taken to be 100%. The relative activities were determined from the product peak integrals using sinapic acid as a standard. For the reverse reaction, disinapoyl spermidine and CoA were used at final concentrations of 100 and 400 μM, respectively, when determining the Km for the other substrate types. All the reactions were run in duplicate, and each experiment was repeated twice. The data represent the mean value (±sd).
The reactions were performed using spermidine as the acyl acceptor.
Not detected.
The reactions were performed using sinapoyl-CoA as the acyl donor.
The reactions were performed using 400 μM CoA as the other substrate.
The reactions were performed using 100 μM disinapoyl spermidine as the other substrate.