Table 2 r in 21 - Hydroxypregnane 21 - O-malonylation, a crucial step in cardenolide biosynthesis, can be achieved by substrate-promiscuous BAHD-type phenolic glucoside malonyltransferases from Arabidopsis thaliana and homolog proteins from Digitalis lanata

Table 2 r At PMaT1 kinetic profiling with different substrates.
SubstrateK M (μM)v (nkat mg 1) maxk(s 1) cat3- O -Acetylketol108 ± 1010.7 ± 0.30.63- O -Digitoxosylketol27 ± 52.6 ± 0.10.14-Pregnen-21-ol-3,20-dione298 ± 620.7 ± 0.060.045α- Pregnane21-ol-3,20-dione374 ± 1230.7 ± 0.10.045β- Pregnan-21-ol-3,20-dione621 ± 1912.5 ± 0.40.15β- Pregnane-3β,21-diol-20-one269 ± 880.7 ± 0.090.04Kaempferol 3- O -glucoside41.5 ± 5353 ± 8619.4Quercetin 3- O -glucoside67 ± 2164 ± 89.0