- Discovery of a cytokinin deaminase
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An enzyme of unknown function within the amidohydrolase superfamily was discovered to catalyze the hydrolysis of N-6-substituted adenine derivatives, several of which are cytokinins. Cytokinins are a common type of plant hormone and N-6-substituted adenines are also found as modifications to tRNA. Patl2390, from Pseudoalteromonas atlantica T6c, was shown to hydrolytically deaminate N-6-isopentenyladenine to hypoxanthine and isopentenylamine with a k cat/Km of 1.2 × 107 M-1 s -1. Additional substrates include N-6-benzyl adenine, cis- and trans-zeatin, kinetin, O-6-methylguanine, N-6-butyladenine, N-6-methyladenine, N,N-dimethyladenine, 6-methoxypurine, 6-chloropurine, and 6-thiomethylpurine. This enzyme does not catalyze the deamination of adenine or adenosine. A comparative model of Patl2390 was computed using the three-dimensional crystal structure of Pa0148 (PDB code 3PAO) as a structural template, and docking was used to refine the model to accommodate experimentally identified substrates. This is the first identification of an enzyme that will hydrolyze an N-6-substituted side chain larger than methylamine from adenine.
- Goble, Alissa M.,Fan, Hao,Sali, Andrej,Raushel, Frank M.
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experimental part
p. 1036 - 1040
(2012/05/20)
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- THE SYNTHESIS OF ALLYLIC PHOSPHATE DERIVATIVES OF TRANS ZEATIN
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Phosphitylation of the allylic hydroxy group in 9-tetrahydropyranyl trans-zeatine with salicyl chlorophosphite gives the allyl phosphonate monoester 5, which can be readily converted into the corresponding phosphate 7, methylphosphate 8 or thiophosphate 9.After cleavage of the tetrahydropyranyl group under mild acidic condition allylic phosphate derivatives of trans-zeatin are obtained.
- Vonk, C.R.,Davelaar, E.,Ribot, S.A.
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p. 3889 - 3896
(2007/10/02)
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