PlantSME Plant secondary metabolism enzyme database
Alkaloid portable pathway

Alkaloid portable pathway

Category:Alkaloid pathway

Alkaloid pathway definition imported from the 2026-05-17 portable BLAST/HMM package.

Representative Alkaloid Reaction Route
BIA, MIA, nicotine/tropane, and purine branches. Alkaloid biosynthesis is not a single route; this page separates BIA, MIA, nicotine/tropane, and purine branches with entry substrates, key enzyme modules, and representative products.
6 curated steps/modules
BIA Benzylisoquinoline Branch
01
Substrate
L-Tyrosine/dopamine
C9H11NO3 / C8H11NO2
catechol-CH2-CH2-NH2
Substrate
4-Hydroxyphenylacetaldehyde
C8H8O2
4-HO-C6H4-CH2-CHO
Dopamine formation and norcoclaurine condensation
Product
(S)-Norcoclaurine
C16H17NO3
benzylisoquinoline tetrahydro core
TYDC/DDC provide aromatic amine substrates, and NCS forms the BIA core.
02
Substrate
Norcoclaurine/reticuline-like intermediates
C16-C19 BIA
benzylisoquinoline scaffold
Methylation, hydroxylation, and downstream BIA diversification
Product
BIA derivatives
benzylisoquinoline alkaloids
O-methylated/bridged BIA scaffolds
OMT/CYP/reductase combinations route norcoclaurine-like intermediates to diverse BIA products.
MIA Monoterpene Indole Alkaloid Branch
03
Substrate
GPP/geraniol
C10H20O7P2 / C10H18O
C10 prenyl-OPP / HO-CH2-C10 isoprenoid
Formation of the terpenoid seco-iridoid donor
Product
Secologanin
C17H24O10
seco-iridoid glucoside aldehyde
The terpenoid branch of MIA biosynthesis generates the secologanin donor from GPP/geraniol-derived intermediates.
04
Substrate
Tryptamine + secologanin
C10H12N2 + C17H24O10
indole-CH2-CH2-NH2 + seco-iridoid aldehyde
Tryptamine condensation and post-strictosidine tailoring
Product
Strictosidine/MIA derivatives
C27H34N2O9 and derivatives
indole-monoterpene alkaloid scaffold
STR couples tryptamine with secologanin; downstream hydrolysis and tailoring yield diverse MIA scaffolds.
Nicotine, Tropane, And Purine Branches
05
Substrate
Ornithine/arginine
C5H12N2O2 / C6H14N4O2
H2N-(CH2)n-CH(NH2)-COOH
Polyamine-derived nicotine/tropane scaffolds
Product
Nicotine/tropane intermediates
N-heterocyclic alkaloids
N-methylpyrrolinium / tropane ring
ODC/ADC/PMT/MPO and related enzymes generate N-methylpyrrolinium-type intermediates for nicotine or tropane directions.
06
Substrate
Xanthine/xanthosine
C5H4N4O2 / nucleoside
purine-2,6-dione ring
Purine methylation
Product
Methylxanthines/caffeine
C8H10N4O2
1,3,7-trimethyl-purine-2,6-dione
XMT/MXMT/DXMT methyltransferases catalyze stepwise methylation of the xanthine scaffold.
Lineage Distribution
Assignments under this module are distributed across the following plant lineages.
Module Gene List
GeneSpeciesProtein ID
acer_truncatum_Atru.chr11.2684 acer_truncatum acer_truncatum_Atru.chr11.2684
acer_truncatum_Atru.chr11.413 acer_truncatum acer_truncatum_Atru.chr11.413
acer_truncatum_Atru.chr11.749 acer_truncatum acer_truncatum_Atru.chr11.749
acer_truncatum_Atru.chr11.782 acer_truncatum acer_truncatum_Atru.chr11.782
acer_truncatum_Atru.chr11.828 acer_truncatum acer_truncatum_Atru.chr11.828
acer_truncatum_Atru.chr11.832 acer_truncatum acer_truncatum_Atru.chr11.832
acer_truncatum_Atru.chr11.987 acer_truncatum acer_truncatum_Atru.chr11.987
acer_truncatum_Atru.chr12.1077 acer_truncatum acer_truncatum_Atru.chr12.1077
acer_truncatum_Atru.chr12.1171 acer_truncatum acer_truncatum_Atru.chr12.1171
acer_truncatum_Atru.chr12.1411 acer_truncatum acer_truncatum_Atru.chr12.1411
acer_truncatum_Atru.chr12.1445 acer_truncatum acer_truncatum_Atru.chr12.1445
acer_truncatum_Atru.chr12.1446 acer_truncatum acer_truncatum_Atru.chr12.1446
acer_truncatum_Atru.chr12.1540 acer_truncatum acer_truncatum_Atru.chr12.1540
acer_truncatum_Atru.chr12.1566 acer_truncatum acer_truncatum_Atru.chr12.1566
acer_truncatum_Atru.chr12.1574 acer_truncatum acer_truncatum_Atru.chr12.1574
acer_truncatum_Atru.chr12.1575 acer_truncatum acer_truncatum_Atru.chr12.1575
acer_truncatum_Atru.chr12.1745 acer_truncatum acer_truncatum_Atru.chr12.1745
acer_truncatum_Atru.chr12.1825 acer_truncatum acer_truncatum_Atru.chr12.1825
acer_truncatum_Atru.chr12.1860 acer_truncatum acer_truncatum_Atru.chr12.1860
acer_truncatum_Atru.chr12.1866 acer_truncatum acer_truncatum_Atru.chr12.1866
acer_truncatum_Atru.chr12.1950 acer_truncatum acer_truncatum_Atru.chr12.1950
acer_truncatum_Atru.chr12.1951 acer_truncatum acer_truncatum_Atru.chr12.1951
acer_truncatum_Atru.chr12.2140 acer_truncatum acer_truncatum_Atru.chr12.2140
acer_truncatum_Atru.chr12.2266 acer_truncatum acer_truncatum_Atru.chr12.2266
acer_truncatum_Atru.chr12.273 acer_truncatum acer_truncatum_Atru.chr12.273
acer_truncatum_Atru.chr12.274 acer_truncatum acer_truncatum_Atru.chr12.274
acer_truncatum_Atru.chr12.275 acer_truncatum acer_truncatum_Atru.chr12.275
acer_truncatum_Atru.chr12.276 acer_truncatum acer_truncatum_Atru.chr12.276
acer_truncatum_Atru.chr12.31 acer_truncatum acer_truncatum_Atru.chr12.31
acer_truncatum_Atru.chr12.365 acer_truncatum acer_truncatum_Atru.chr12.365