Lyase activity of nucleoside 2-deoxyribosyltransferase: transient generation of ribal and its use in the synthesis of 2'-deoxynucleosides.
In the absence of acceptors nucleoside 2-deoxyribosyltransferase catalyzes the slow hydrolysis of 2'-deoxynucleosides. During this hydrolytic reaction, D-ribal (1,4-anhydro-2-deoxy-D-erythro-pent-1-enitol), a glycal of ribose hitherto encountered only as a reagent in organic synthesis, is generated spontaneously, disappearing later as 2'-deoxynucleoside hydrolysis approaches completion. Nucleoside 2-deoxyribosyltransferase is found to catalyze the hydration of D-ribal in the absence of nucleic acid bases and the synthesis of deoxyribonucleosides from ribal in their presence, affording a new method for the preparation of 2'-deoxyribonucleosides. The stereochemistry of nucleoside formation from ribal supports the intervention of deoxyribosyl-enzyme intermediate. The equilibrium constant for the covalent hydration of ribal is found to be approximately 65.
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Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill 27599.
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Wolfenden
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D003837:Deoxy Sugars / Q000378:metabolism*; D003853:Deoxyribonucleosides / Q000096:biosynthesis*; D007700:Kinetics; D007778:Lactobacillus / Q000201:enzymology*; D008190:Lyases / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D010429:Pentoses / Q000378:metabolism*; D010430:Pentosyltransferases / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism
D003837:Deoxy Sugars; D003853:Deoxyribonucleosides; D010429:Pentoses; C070313:ribal; D010430:Pentosyltransferases; C021888:nucleoside deoxyribosyltransferase; D008190:Lyases; D013936:Thymidine