Table S4.
IAA and BA kinetics of IAA-conjugating GH3 proteins
| Kinetic parameter | AtGH3.5 | AtGH3.1 | AtGH3.2 | AtGH3.17 |
| kcat IAA, min−1 | 14.5 ± 1.4 | 5.7 ± 0.6 | 17.0 ± 1.6 | 2.7 ± 0.1 |
| KmIAA, μM | 770 ± 110 | 530 ± 150 | 510 ± 105 | 68.0 ± 6.0 |
| kcat/KmIAA, M−1⋅s−1 | 314 | 179 | 556 | 662 |
| kcat PAA, min−1 | 28.0 ± 2.0 | 4.8 ± 0.8 | 19.5 ± 0.5 | 3.0 ± 0.1 |
| KmPAA, μM | 1,840 ± 233 | 3,075 ± 760 | 2,525 ± 174 | 268 ± 7.8 |
| kcat/KmPAA, M−1⋅s−1 | 253 | 26 | 125 | 187 |
| kcat BA, min−1 | 16.0 ± 0.8 | 2.7 ± 0.7 | 2.2 ± 0.6 | 0.87 ± 0.08 |
| KmBA, μM | 790 ± 60 | 3,350 ± 1,340 | 4,760 ± 285 | 1,090 ± 222 |
| kcat/KmBA, M−1⋅s−1 | 338 | 13 | 77 | 13 |
AtGH3.5 values are from Table S2 and are shown for comparison with other A. thaliana GH3 proteins. Average values ± SD (n = 3–5) are shown for steady-state kinetic parameters. Assays were performed as described with fixed concentrations of ATP (1 mM) and Asp (10 mM for AtGH3.5 and AtGH3.2), Asn (10 mM for AtGH3.1), or Glu (10 mM for AtGH3.17) and with varied concentrations of IAA, PAA, or BA (up to 10 x Km value).