Research Progress relating to the role of cytochrome P450 in the biosynthesis of

terpenoids in medicinal plants

Yu-Jun Zhao.Qi-Qing.Ping Su.Xin Chen.Xiu-juan.Wei.Lu-QiBy judy mutua

Introduction

Terpenoids are plant natural products with isoprene as their structural unit.

Terpenoid Biosynthesis

Terpenoid Biosynthesis

Cytotochrome P450

• Hemoproteins-The active site of cytochrome P450 contains a heme-iron center.

CYP450 Spectrum

• The term P450 is derived from the spectrophotometric peak at the wavelength of the absorption maximum of the enzyme (450 nm) when it is in the reduced state and complexed with CO

Different cytochrome P450 systems

• Most CYPs require a protein partner to deliver one or more electrons.

Examples of plant cytochromesP450 Function Plant SpeciesCYP93E2 β-Balsams alcohol-11-

hydroxylaseBarrel Clover (Medicago truncatula)

CYP71AV1 Amorpha-4,11-diene C-12 oxidase

Artemesia annua

CYP76B6 Geraniol 10-hydroxylase

Madagascar periwinkle (Catharanthus roseus)

CYP725A-like Taxadiene 5-α-hydroxylase

Japanese Yew (Taxus cuspidata)

CYP88D6 Β-Amyrin 11-oxidase Chinese liquorice (Glycyrrhiza uralensis)

Chinese liquorice(Glycyrrhiza uralensis)

• The main active Ingredient is glycyrrhizicacid used to treat cancer& AIDS.

Biosynthesis of Glycyrrhizin.

Identification of Licorice β-amyrin 11-oxidase

CYP72 CYP83 CYP88 CYP714 ↘ ↓ ↓ ↙

Conversion of β-amyrin

Transfected insect cells

Identification of Licorice β-amyrin 11-oxidase

Challenges in Terpenoid synthesis

• Low abundance in their host organism. • low yields .• high consumption of natural resources.• Chemical synthesis difficult to scale for

industrial production.

Comparison of hostsCharacteristic Bacterial cells Plant cellsSize 1µm 20-50µmShear stress Insensitive SensitiveDoubling Time < 1 hour DaysBatch Fermentation time

Days Weeks

Product Yields High lowPrecursors poor richNative conditions no yesCYP450 enzymes Absent present

Conclusion

• Traditional engineering strategies result to unbalanced carbon flux and accumulation of toxic intermediates that inhibit growth.

• The utilisation of genetic engineering to regulate gene expression and obtain large quantities of terpene compounds should be explored fully.