Journal article
Purification and characterization of taxa-4(5),11(12)-diene synthase from Pacific yew (Taxus brevifolia) that catalyzes the first committed step of taxol biosynthesis
Archives of biochemistry and biophysics, Vol.322(2), pp.437-444
10/01/1995
Handle:
https://hdl.handle.net/2376/110800
PMID: 7574719
Abstract
The first step in the biosynthesis of taxol in Pacific yew (Taxus brevifolia) is the cyclization of the universal diterpene precursor geranylgeranyl pyrophosphate to taxa-4(5),11(12)-diene. This parent olefin of the taxane diterpenoids is then elaborated to taxol and related compounds by a complex series of reactions involving oxidations and side-chain acylations. Cyclization activity is located principally in yew stem bark and adhering cambium. The operationally soluble cyclization enzyme was partially purified (approximately 600-fold) by combination of anion exchange, hydrophobic interaction, and dye-ligand chromatography. Nondenaturing, followed by denaturing, polyacrylamide gel electrophoresis, in combination with gel permeation chromatography, allowed the identification of taxadiene synthase as a monomeric protein of molecular weight 79,000. In general properties (divalent metal ion requirement, kinetic constants, molecular weight), the taxadiene synthase of Pacific yew is similar to the diterpene cyclase abietadiene synthase involved in resin acid biosynthesis in other gymnosperms. However, in pH optimum and response to inhibitors, these two diterpene cyclases are distinctly different. The activity (and enzyme protein) levels of Pacific yew taxadiene synthase are much lower than those for abietadiene synthase of lodgepole pine stem (constitutive) or of grand fir stem (wound-inducible) and the enzyme is not inducible to higher levels by stem wounding or elicitor treatment.
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Details
- Title
- Purification and characterization of taxa-4(5),11(12)-diene synthase from Pacific yew (Taxus brevifolia) that catalyzes the first committed step of taxol biosynthesis
- Creators
- M Hezari - Institute of Biological Chemistry, Washington State University, Pullman 99164-6340, USAN G LewisR Croteau
- Publication Details
- Archives of biochemistry and biophysics, Vol.322(2), pp.437-444
- Academic Unit
- Biological Chemistry, Institute of
- Publisher
- United States
- Grant note
- CA-55254 / NCI NIH HHS
- Identifiers
- 99900546905701842
- Language
- English
- Resource Type
- Journal article