Molecules 2013, 18(10), 12587-12598; doi:10.3390/molecules181012587
Article

Enzymatic Synthesis of Highly Fluorescent 8-Azapurine Ribosides Using a Purine Nucleoside Phosphorylase Reverse Reaction: Variable Ribosylation Sites

Received: 30 August 2013; in revised form: 25 September 2013 / Accepted: 30 September 2013 / Published: 11 October 2013
(This article belongs to the Special Issue Synthesis of Nucleosides, Nucleotides and Their Derivatives)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Various forms of purine-nucleoside phosphorylase (PNP) were used as catalysts of enzymatic ribosylation of selected fluorescent 8-azapurines. It was found that the recombinant calf PNP catalyzes ribosylation of 2,6-diamino-8-azapurine in a phosphate-free medium, with ribose-1-phosphate as ribose donor, but the ribosylation site is predominantly N7 and N8, with the proportion of N8/N7 ribosylated products markedly dependent on the reaction conditions. Both products are fluorescent. Application of the E. coli PNP gave a mixture of N8 and N9-substituted ribosides. Fluorescence of the ribosylated 2,6-diamino-8-azapurine has been briefly characterized. The highest quantum yield, ~0.9, was obtained for N9-β-d-riboside (λmax 365 nm), while for N8-β-d-riboside, emitting at ~430 nm, the fluorescence quantum yield was found to be close to 0.4. Ribosylation of 8-azaguanine with calf PNP as a catalyst goes exclusively to N9. By contrast, the E. coli PNP ribosylates 8-azaGua predominantly at N9, with minor, but highly fluorescent products ribosylated at N8/N7.
Keywords: 8-azapurines; nucleosides; enzymatic synthesis; fluorescence; purine-nucleoside phosphorylase
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MDPI and ACS Style

Stachelska-Wierzchowska, A.; Wierzchowski, J.; Wielgus-Kutrowska, B.; Mikleušević, G. Enzymatic Synthesis of Highly Fluorescent 8-Azapurine Ribosides Using a Purine Nucleoside Phosphorylase Reverse Reaction: Variable Ribosylation Sites. Molecules 2013, 18, 12587-12598.

AMA Style

Stachelska-Wierzchowska A, Wierzchowski J, Wielgus-Kutrowska B, Mikleušević G. Enzymatic Synthesis of Highly Fluorescent 8-Azapurine Ribosides Using a Purine Nucleoside Phosphorylase Reverse Reaction: Variable Ribosylation Sites. Molecules. 2013; 18(10):12587-12598.

Chicago/Turabian Style

Stachelska-Wierzchowska, Alicja; Wierzchowski, Jacek; Wielgus-Kutrowska, Beata; Mikleušević, Goran. 2013. "Enzymatic Synthesis of Highly Fluorescent 8-Azapurine Ribosides Using a Purine Nucleoside Phosphorylase Reverse Reaction: Variable Ribosylation Sites." Molecules 18, no. 10: 12587-12598.

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