Table 2.
Specificity of recombinant GA 2-oxidases for C19-GA substrates
| Recombinant enzyme | 14C-labeled GA substrate | 2β-HydroxyGA product | GA-catabolite product |
|---|---|---|---|
| Pc2ox1 | GA1 | 100 | — |
| GA4 | 83 | 17 | |
| GA9 | 87 | 13 | |
| GA20 | 86 | — | |
| At2ox1 | GA1 | 41 | — |
| GA4 | 25 | — | |
| GA9 | 91 | — | |
| GA20 | 50 | — | |
| At2ox2 | GA1 | 100 | — |
| GA4 | 77 | 23 | |
| GA9 | — | 100 | |
| GA20 | 100 | — | |
| At2ox3 | GA1 | 100 | Trace |
| GA4 | 86 | 14 | |
| GA9 | 100 | — | |
| GA20 | 25 | — |
Values are % yield by HPLC-radiomonitoring of products after incubation of cell lysates from E. coli expressing the cDNA with 14C-labeled GA substrate and cofactors for 2.5 h. Products and substrate were separated by HPLC, and products were identified by GC/MS (see Fig. 2). Where combined yield of products is <100%, the remainder is unconverted substrate.