Biosynthesis metabolic channels

Jorgensen K, Rasmussen AV, Morant M, Nielsen AH, Bjarnholt N, Zagrobelny M, Bak S, Moller BL. (2005). Metabolon formation and the metabolic channelling in the biosynthesis of NPs. Current Opinion in Plant Science, 8,280-291. 

Achnine L, Blancaflor EB, Rasmussen S, Dixon RA. 2004. Colocalization of L-phenylalanine ammonia-lyase and cinnamate 4-hydroxylase for metabolic channeling in phenylpropanoid biosynthesis. Plant Cell 16 3098-3109. 

Jorgensen, K., Rasmussen, A.V., Morant, M., Nielsen, A.H., Bjanrholt, N., Zagrobelny, M., Bak, S. and Moller, B.L. (2005) Metabolon formation and metabolic channeling in the biosynthesis of plant natural products. Curr. Opin. Plant Biol., 8, 280-91. 

Jandt, U., You, C., Zhang, Y.H., and Zeng, A.P. (2013) Compartmental-ization and metabolic channeling for multienzymatic biosynthesis practical strategies and modeling approaches. 

Despite the detection of COR and other known morphinan branch pathway enzymes in opium poppy cell cultures (63-65,67), morphine and codeine are not produced. The inability of cultured cells to accumulate morphine might reflect the absence of other relevant enzymes or structural proteins that preclude the formation of a requisite metabolic channel. Nevertheless, the efficient operation of the sang-uinarine pathway indicates that cultured opium poppy cells possess the essential regulatory, eellular, and metabolic components to support the biosynthesis and... 

Many plants utilize different PAL isoforms for stress responses or for biosynthesis of structural components, and these different PALs exhibit differential expression in distinct tissues. Metabolic channeling may help control the flux of phenylalanine through PAL into the different phenylpropanoid branch pathways [6,7]. 

Jorgensen, K.et al. (2005) Metabolon formation and metabolic channeling in the biosynthesis of plant natural products. Curr. Opin. Plant Biol. 8, 280-291... 

The existence of a metabolic channel wonld be in line with the regnlatory independence of the enzymes of the morphinane branch from the general benzylisoqninohne biosynthesis. A well known expression of this phenomenon is the intimate link between lacticifer development and biosynthesis of morphine dedifferentiated, cultured cells of opium poppy do not prodnce... 

A simplified view of metabolism is to consider a cell as a "bag of enzymes." Indeed, much of metabolism can be explained by the action of several thousand enzymes promoting specific reactions of their substrates. These reactions are based upon the natural chemical reactivities of the substrates. However, the enzymes, through the specificity of their actions and through association with each other,96 221 223 channel the reactions into a selected series of metabolic pathways. The reactions are often organized as cycles which are inherently stable. We have seen that biosynthesis often involves ATP-dependent reductive reactions. 

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