Isoprenoids metabolism

Vandenbergh PA, AM Wright (1983) Plasmid involvement in acyelic isoprenoid metabolism by Pseudomonas putida. Appl Environ Microbiol 45 1953-1955. 

Krits, R, Fogelman, E., Ginzberg, I. (2007). Potato steroidal glycoalkaloid levels and the expression of key isoprenoid metabolic genes. Planta, 227, 143-150. 

Investigations of isoprenoid metabolism and biochemistry in plants have been hampered for several reasons. Some isoprenoids accumulate over long developmental time courses, which suggests that the enzymes responsible for their biosynthesis are either present in low abundance or have low activity levels. Sterols... 

Figure 10.5 Plant cell cultures have proven to be very useful for studying plant-pathogen interactions and isoprenoid metabolism. Tobacco cell cultures respond rapidly to the addition of fungal elicitors (0.5 pg cellulase/ml of culture) by browning (A) (analogous to a hypersensitive response) and the production of phytoalexins (B). Media was collected from elicited cell cultures at the indicated times, partitioned against an organic solvent, and concentrated aliquots run on a silica TLC plate. The plates were then sprayed with a suspension of Cladosporium cucumerinum spores and incubated in a humid environment for 5 days before viewing (B). The compound released from the elicitor-treated tobacco cells that inhibits spore germination is capsidiol, a sesquiterpene.

Shiba Y, Paradisea EM, Kirbya J, Ro D-K Keasling JD. Engineering of the pyruvate dehydrogenase bypass in Saccharomyces cerevisiae for high-level production of isoprenoids. Metabol. Eng. 2007 9 160-168. 

MEMBRANE BIOGENESIS Sphingolipid Metabolism ISOPRENOID METABOLISM... 

Relatively little is known about plant sterols. (Most of the research effort in steroid metabolism has been expended in the investigation of steroid-related human diseases.) It appears, however, that the initial phase of plant sterol synthesis is very similar to that of cholesterol synthesis with the following exception. In plants and algae the cyclization of squalene-2,3-epoxide leads to the synthesis of cycloartenol (Figure 12.30) instead of lanosterol. Many subsequent reactions in plant sterol pathways involve SAM-mediated methylation reactions. There appear to be two separate isoprenoid biosynthetic pathways in plant cells the ER/cyto-plasm pathway and a separate chloroplast pathway. The roles of these pathways in plant isoprenoid metabolism are still unclear. 

Fig. 11.3 Simplified diagram of isoprenoid metabolic pathway relative to the conversions among carotenoids that have been genetically manipulated. Enzymes catalysing some key reactions are indicated by the following abbreviations IPI, isopentenyl pyrophosphate isomerase PSY, phytoene synthase PDS, phytoene desaturase (crti, gene from Erwinia uredovora) ZDS, -carotene desaturase LCYB, lycopene / -cyclase CRTR-b, /3-carotene 3,3 -hydroxylase CCS, capsanthin-capsombin synthase CRTO, /3-carotene ketolase.

Isopentenyl diphosphate (IPP) isomerase catalyzes the conversion of IPP to dimethylallyl diphosphate (DMAPP), an early step in isoprenoid metabolism (Equation (25)). 

Wiemer AJ, Hohl RJ, Wiemer DF (2009) The intermediate enzymes of isoprenoid metabolism as anticancer targets. Anticancer Agents Med Chem 9 526-542... 

Wiemer AJ, Hsiao CH, Wiemer DF (2010) Isoprenoid metabolism as a therapeutic target in Gram-negative pathogens. Curr Top Med Chem 10 1858-1871... 

Ayabe S, Nagashima S, Furuno T, Takahashi T, Yuki TT, Hirota H (1991) Growth and isoprenoid metabolism of cultured Picrama quassioides cells. Plant Tissue Cult Lett 8 198-200... 

Bramley PM (1997) Isoprenoid metabolism. In Dey PM, Harbome JB (eds) Plant biochemistry. Academic Press, San Diego, USA, pp 417-437... 

C-pyruvate appeared to be shifted in favour of lipid fractions originating from isoprenoid metabolism. 

Fig. 4. Scheme to illustrate the changes of isoprenoid metabolism during maturation of chloroplasts in different regions of the leaf, (left) The formation of isopre-noids (e.g. carotene) from photosynthetically fixed CO2 via plastidic IPP synthesis in developing chloroplasts and the basal region of the leaf, (right) Decrease of the plastidic activity for IPP synthesis and import of IPP from the cytosol into fully photosynthetically active, mature chloroplast at the tip of the leaf. 

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