This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Biosynthesis → Hormones Biosynthesis → Plant Hormones Biosynthesis → Cytokinins Biosynthesis|
Some taxa known to possess this pathway include : Arabidopsis thaliana col
Expected Taxonomic Range: Embryophyta
Glucosylation of cytokinins is a well recognized modification that is thought to play an important role in hormonal homeostasis. Several types of cytokinins conjugation exist which render cytokinins inactive: O-xylosylation, O-glucosylation, and N-glucosylation. When plants are subjected to high levels of cytokinin application, the major conjugate that forms is the 7-N-glucoside (see cytokinins 7-N-glucoside biosynthesis) [Hou04]. Moreover, unlike O-glucosides, the glucosylation of which is reversible through the action of glucosidases, 7-N- and 9-N-glucosides are resistant to glucosidases [Brzobohaty93]. This, taken with N-glucosides accumulation in plant subjected to high doses of cytokinins, has led to the suggestion that N-glucosylation is involved in detoxification [Hou04]. It is not yet known whether glucosylation at position 9-N plays a specific role or whether it is merely a byproduct of the 7-N-glucosylation.
Unification Links: AraCyc:PWY-2901
Brzobohaty93: Brzobohaty B, Moore I, Kristoffersen P, Bako L, Campos N, Schell J, Palme K (1993). "Release of active cytokinin by a beta-glucosidase localized to the maize root meristem." Science 262(5136);1051-4. PMID: 8235622
Kasahara04: Kasahara H, Takei K, Ueda N, Hishiyama S, Yamaya T, Kamiya Y, Yamaguchi S, Sakakibara H (2004). "Distinct isoprenoid origins of cis- and trans-zeatin biosyntheses in Arabidopsis." J Biol Chem 279(14);14049-54. PMID: 14726522
Takei04: Takei K, Yamaya T, Sakakibara H (2004). "Arabidopsis CYP735A1 and CYP735A2 encode cytokinin hydroxylases that catalyze the biosynthesis of trans-Zeatin." J Biol Chem 279(40);41866-72. PMID: 15280363
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