Specialized Metabolites
Terpenoids, alkaloids, flavonoids, and anthocyanins — the chemical arsenal plants deploy for defense, attraction, and UV protection.
Specialized Metabolite Overview
Foundational Chemistry
IPP condensation (head-to-tail)
\( \text{IPP} + \text{DMAPP} \xrightarrow{\text{prenyltransferase}} \text{GPP} \, (\text{C}_{10}) \)
CHS reaction (chalcone synthesis)
\( \text{p-coumaroyl-CoA} + 3\,\text{malonyl-CoA} \xrightarrow{\text{CHS}} \text{naringenin chalcone} \)
Strictosidine synthase (Pictet-Speraserase)
\( \text{secologanin} + \text{tryptamine} \xrightarrow{\text{STR}} \text{strictosidine} \)
MEP pathway net
\( \text{pyruvate} + \text{G3P} \xrightarrow{7\,\text{steps}} \text{IPP} + \text{DMAPP} \)
Chapters
Chapter 13: Terpenoid Biosynthesis
IPP and DMAPP as C5 building blocks, MEP (plastidial) and MVA (cytosolic) pathways, prenyl transferases, terpene synthases, carotenoid biosynthesis, and isoprene emission.
Chapter 14: Alkaloid Biosynthesis
Classification by precursor amino acid: Trp-derived indole alkaloids, Tyr-derived benzylisoquinolines (morphine, berberine), Lys-derived piperidine alkaloids, Orn-derived tropane alkaloids, and purine alkaloids (caffeine).
Chapter 15: Flavonoids & Anthocyanins
Chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase, dihydroflavonol reductase, anthocyanidin synthase, pH-dependent pigmentation, and proanthocyanidins.