Chemoenzymatic synthesis of cytokinins from nucleosides: ribose as a blocking group

2018 ◽  
Vol 16 (12) ◽  
pp. 2156-2163 ◽  
Author(s):  
Vladimir E. Oslovsky ◽  
Pavel N. Solyev ◽  
Konstantin M. Polyakov ◽  
Cyril S. Alexeev ◽  
Sergey N. Mikhailov

Cytokinin synthesis based on the irreversible enzymatic cleavage by purine nucleoside phosphorylase in the presence of Na2HAsO4 has been developed.

Synthesis ◽  
2017 ◽  
Vol 49 (21) ◽  
pp. 4853-4860 ◽  
Author(s):  
Igor Mikhailopulo ◽  
Alexandra Denisova ◽  
Yulia Tokunova ◽  
Ilja Fateev ◽  
Alexandra Breslav ◽  
...  

Two approaches to the chemoenzymatic synthesis of 2-fluorocordycepin and 2-chlorocordycepin were studied: (i) the use of 3′-deoxyadenosine (cordycepin) and 3′-deoxyinosine (3′dIno) as donors of 3-deoxy-d-ribofuranose in the transglycosylation of 2-fluoro- (2FAde) and 2-chloroadenine (2ClAde) catalyzed by the recombinant E. coli purine nucleoside phosphorylase (PNP), and (ii) the use of 2-fluoroadenosine and 3′-deoxyinosine as substrates of the cross-glycosylation and PNP as a biocatalyst. An efficient method for 3′-deoxyinosine synthesis starting from inosine was developed. However, the very poor solubility of 2ClAde and 2FAde is the limiting factor of the first approach. The second approach enables this problem to be overcome and it appears to be advantageous over the former approach from the viewpoint of practical synthesis of the title nucleosides. The 3-deoxy-α-d-ribofuranose-1-phosphate intermediary formed in the 3′dIno phosphorolysis by PNP was found to be the weak and marginal substrate of E. coli thymidine (TP) and uridine (UP) phosphorylases, respectively. Finally, one-pot cascade transformation of 3-deoxy-d-ribose in cordycepin in the presence of adenine and E. coli ribokinase, phosphopentomutase, and PNP was tested and cordycepin formation in ca. 3.4% yield was proved.


1990 ◽  
Vol 55 (12) ◽  
pp. 2987-2999 ◽  
Author(s):  
Katarina Šedivá ◽  
Ivan Votruba ◽  
Antonín Holý ◽  
Ivan Rosenberg

Purine nucleoside phosphorylase (PNP) from mouse leukemia cells L1210 was purified to homogeneity by a combination of ion exchange and affinity chromatography using AE-Sepharose 4B and 9-(p-succinylaminobenzyl)hypoxanthine as the matrix and the ligand, respectively. The native enzyme has a molecular weight of 104 000 and consists of three subunits of equal molecular weight of 34 000. The results of isoelectric focusing showed that the enzyme is considerably microheterogeneous over the pI-range 4.0-5.8 and most likely consists of eight isozymes. The temperature and pH-optimum of phosphorolysis, purine nucleoside synthesis and also of transribosylation is identical, namely 55 °C and pH 7.4. The transribosylation reaction proceeds in the presence of phosphate only. The following Km-values (μmol l-1) were determined for phosphorolysis: inosine 40, 2'-deoxyinosine 47, guanosine 27, 2'-deoxyguanosine 32. The Km-values (μmol l-1) of purine riboside and deoxyriboside synthesis are lower than the values for phosphorolysis (hypoxanthine 18 and 34, resp., guanine 8 and 11, resp.). An affinity lower by one order shows PNP for (-D-ribose-1-phosphate, (-D-2-deoxyribose-1-phosphate (Km = 200 μmol l-1 in both cases) and phosphate (Km = 805 μmol l-1). The substrate specificity of the enzyme was also studied: positions N(1), C(2) and C(8) are decisive for the binding of the substrate (purine nucleoside).


1986 ◽  
Vol 3 (4) ◽  
pp. 353-359 ◽  
Author(s):  
Ger T. Rijkers ◽  
Ben J. M. Zegers ◽  
Leo J. M. Spaapen ◽  
Derk H. Rutgers ◽  
John J. Roord ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document