Cytokinin dehydrogenase

In enzymology, a cytokinin dehydrogenase (EC 1.5.99.12) is an enzyme that catalyzes the chemical reaction

N⁶-dimethylallyladenine + electron acceptor + H₂O ${\displaystyle \rightleftharpoons }$ adenine + 3-methylbut-2-enal + reduced acceptor

The 3 substrates of this enzyme are cytokinin (here represented by ), electron acceptor, and H₂O, whereas its 3 products are adenine, (or other aldehyde in case of different substrate), and reduced acceptor.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with other acceptors. The systematic name of this enzyme class is N⁶-dimethylallyladenine:acceptor oxidoreductase. Other names in common use include N⁶-dimethylallyladenine:(acceptor) oxidoreductase, 6-N-dimethylallyladenine:acceptor oxidoreductase, and cytokinin oxidase/dehydrogenase abbreviated as CKX.

Structural studies[]

As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes 1W1O, 1W1Q, 1W1R, 1W1S, 2EXR, and 2Q4W.

As of March 2016, there have been 18 structures deposited to PDB. 16 of these were of enzymes from maize and two from Arabidopsis.

References[]

• Galuszka P, Frébort I, Šebela M, Sauer P, Jacobsen S, Peč P (2001). "Cytokinin oxidase or dehydrogenase? Mechanism of cytokinin degradation in cereals". Eur. J. Biochem. 268 (2): 450–461. doi:10.1046/j.1432-1033.2001.01910.x. PMID 11168382.