Plant cell culture benzylisoquinolines from

The lack of strict specificity for the enzymes involved in the initial conversion to (5)-reticuline (20) suggests that stereochemical control does not occur at this stage of biosynthesis (Zenk, 1985). The use of plant cell cultures (both callus and suspension types) from different species of plants that produce benzylisoquinoline alkaloids has proven to be a powerful approach for the isolation of enzymes and intermediates in the pathways leading to these compounds (Zenk et al., 1985). For example, the use of cell-free extracts of Berberis cultures permitted Zenk and co-workers to isolate and characterize all eight enzymes involved in the conversion of dopamine (22) and 4-hydroxyphenylacetaldehyde (19) to (5)-reticuline and, subsequently, to berberine. 

Table 1. Benzylisoquinoline alkaloids isolated from plant cell cultures...

As another example of the value of enzymological studies, the major enzymes of the benzylisoquinoline alkaloid pathway have also been isolated from plant tissue culture and studied by Zenk and co-workers (see Chapter 34) (Fig. 1.2). An enzyme, (S)-norlaudanosoline synthase, which catalyzes the conversion of dopamine and (3,4-dihydroxyphen-yl)acetaldehyde (9) into (S)-norlaudanosoline (10) has been purified about 40-fold from cell suspension cultures of Eschscholtzia tenuifolia (see also cluster 32 for up-dated in-... 

Scott AI, Lee SL, Hirata T, Culver MG (1978a) Biosynthesis of plant products using cell free systems from tissue cultures. Rev. Latinoam Quim 9 131-138 Scott AI, Lee SL, Hirata T (1978b) The early stages of Papaver alkaloid biosynthesis. Cell-free synthesis of benzylisoquinolines. Heterocycles 11 159-163 Shamma M (1972) The isoquinoline alkaloids. Academic, London New York... 

Roberts MF, Antoun MD (1978) The relationship between L-DOPA decarboxylase in the latex of Papaver somniferum and alkaloid formation. Ph3rtochemistry 17 1083-1087 Roberts MF, McCarthy D, Kutchan TM, Coscia CJ (1983) Localization of enzyme and alkaloidal metabolites in Papaver latex. Arch Biochem Biophys 222 599-609 Rueffer M, El-Shagi H, Nagakura N, Zenk MH (1981) (S)-Norlaudanosoline synthetase the first enzyme in the benzylisoquinoline biosynthetic pathway. FEBS Lett 129 5-9 Sasse F, Backs-Hiisemann D, Barz W (1979) Isolation and characterization of vacuoles from cell suspension cultures of Daucus carota. Z Naturforsch 34 848-853 Schuchmann R, Wellmann E (1983) Somatic embryogenesis of tissue cultures of Papaver somniferum and Papaver orientate and its relationship to alkaloid and lipid metabolism. Plant Cell Rep 2 88-91... 

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