Metabolism of Cytokinin: Deribosylation of Cytokinin Ribonucleoside by Adenosine Nucleosidase from Wheat Germ Cells
Year: 1981
Type: article
Abstract: Adenosine nucleosidase (adenosine ribohydrolase, EC 3.2.2.7) which catalyzes the deribosylation of N(6)-(Delta(2)-isopentenyl)adenosine and adenosine to form the corresponding bases was partially purified from wheat germ. This enzyme (molecular weight 59,000 +/- 3,000) deribosylates the ribonucleosides at an optimum pH of 4.7 K(m) values for the cytokinin nucleoside and adenosine are 2.38 and 1.43 micromolar, respectively, in 50 millimolar Tris-citrate buffer (pH 4.7) at 30 C. The presence of adenosine and other cytokinin nucleosides inhibited the hydrolysis of N(6)-(Delta(2)-isopentenyl)adenosine but this reaction was insensitive to guanosine, uridine, or 3'-deoxyadenosine. It is hypothesized that an adequate level of "active cytokinin" in plant cells may be provided through the deribosylation of cytokinin riboside in concert with other cytokinin metabolic enzymes.
Source: PLANT PHYSIOLOGY
DOI: 10.1104/pp.68.5.1020
Authors: Chong-Maw Chen, Susan M. Kristopeit
Institution: University of Wisconsin–Parkside
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: bronze
Funder: National Science Foundation
OpenAlex ID: W2056725258