Table 2 Putative key enzymes involved in the triterpenoid saponins biosynthesis pathway in P. grandiflorus.

AACT (acetoacetyl-coenzyme A)

2.3.1.9

HMGS (hydroxymethylglutaryl-CoA synthase)

2.3.3.10

HMGR (3-hydroxy-3-methylglutaryl-coenzyme A reductase)

1.1.1.34

MVK (mevalonate kinase)

2.1.7.36

PMK (phosphomevalonate kinase)

2.7.4.2

MVD (mevalonate diphosphate decarboxylase)

4.1.1.33

GPPS (geranylgeranyl pyrophosphate synthase)

2.5.1.29

FPPS (Farnesyl-diphosphate synthase)

2.5.1.1, 2.5.1.10

SS (squalene synthase)

2.5.1.21

SE (squalene epoxidase)

1.14.14.17

β-AS (beta-amyrin synthase)

5.4.99.39

β-A28O (isolate CYP716A140 beta-amyrin 28-oxidase)

1.14.13.-

LS (lupeol synthase)

5.4.99.41

CAS (cycloartenol synthase)

5.4.99.8

IDI (isopentenyl-diphosphate Delta-isomerase)

5.3.3.2

DXS (1-deoxy-D-xylulose 5-phosphate synthase)

2.2.1.7

DXR (1-deoxy-D-xylulose 5-phosphate reductoisomerase)

1.1.1.267

CMS (2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase

(4-diphosphocytidyl-2C-methyl-D-erythritol synthase))

2.7.7.60

CMK (4-diphosphocytidyl-2-C-methyl-D-erythritol kinase)

2.7.1.148

MCS (2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase)

4.6.1.12

HDS ((E)-4-hydroxy-3-methylbut-2-enyl-diphosphate synthase)

1.17.7.1, 1.17.1.3

HDR (4-hydroxy-3-methylbut-2-enyl diphosphate reductase)

1.17.1.4

ACM59590 (β-Glucosidase)

3.2.1.21