Terpenoid indole alkaloids peroxidases

Sottomayor M, Cardoso IL, Pereira LG, Barcel AR. Peroxidase and the biosynfiiesis of terpenoid indole alkaloids in file medicinal plant Cafiiaranfiius roseus (L.) G. Don.. Phytochem. Rev. 

Fig. (3). Compartmentalization of the biosynthetic pathway of terpenoid indole alkaloids in plant cells. G10H geraniol 16-hydroxylase SLS secologanin synthase TDC tryptophan decarboxylase STR strictosidine synthase SGD strictosidine P-D-glucosidade T16H tabersonine 16-hydroxylase OMT S-adenosyl - L-methionine 16-hydroxytabereonine - 16-O-methyltransferase NMT S-adenosyl - /.-methionine 16-methoxy - 2,3-dihydro-3-hydroxytabersonine - A -methyltransferase D4H desacetoxy vindoline 4-hydroxylase DAT acetylcoenzyme A 4-O-deacetylvindoline 4-O-aeetyltransferase PRX peroxidase.

Terpenoid indole alkaloid biosynthetic enzymes are associated with at least three different cell types in C. roseus TDC and STR are localized to the epidermis of aerial organs and the apical meristem of roots, D4H and DAT are restricted to the laticifers and idio-blasts of leaves and stems, and GlOH is found in internal parenchyma of aerial organs (St-Pierre et al. 1999 Buriat et al. 2004) thus, vindoline pathway intermediates must be translocated between cell types. Moreover, enzymes involved in terpenoid indole alkaloid biosynthesis in C. roseus are also localized to at least five subcellular compartments TDC, D4H and DAT are in the cytosol, STR and the peroxidase that couples catharanthine to vinblastine are localized to the vacuole indicating transport of tryptamine across the tono-plast, SGD is a soluble enzyme associated with the cytoplasmic face of the endoplasmic reticulum, the P450-dependent monooxygenases are integral endomembrane proteins, and the N-methyltransferase involved in vindoline biosynthesis is localized to thylakoid membranes (De Luca and St-Pierre 2000). 

Nevertheless, the substrate specificity of peroxidases is so wide that secretory plant peroxidases are capable of accepting a plethora of natural compounds as substrates, such as indoles [43], porphyrins [44,45] including chlorophylls [46,47], terpenoids such as lutein [48], unsaturated lipid acids such as linoleic acid [49], alkaloids [50-52] including betacyanins [53], phenolics such as benzoic acids [54,55], DOPA [56], coumarins [38,57], stylbenes [58], catechins [36,59], chalcones [60], flavonols [61,62], isoflavones [63,64], cinnamyl alcohols and cinnamic acids [65,66], anthocyanins [67,68] and ascorbic acid [69,70],... 

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