Azotobacter vinelandii polynucleotide phosphorylase

Similarly, Ikehara, Tazawa, and Fukui (51) have found that the nucleotides 8-bromo and 8-oxoadenosine 5 -diphosphate, 8-bromo-, 8-oxo, and 8-dimethylaminoguanosine 5 -diphosphate are all inactive as substrates for homopolymer synthesis catalyzed by polynucleotide phosphorylase from Escherichia coli. Some of the results were later confirmed by Kapuler, Monny, and Michelson (52), who found that neither 8-bromo- nor 8-oxoguanosine 5 -diphosphate was active as a substrate for homopolymerization with polynucleotide phosphorylases isolated both irom Azotobacter vinelandii and . coli. 

G17. Grunberg-Manago, M., Ortiz, P. J., and Ochoa, S., Enz3rmic sjmthesis of polynucleotides. I. Polynucleotide phosphorylase of Azotobacter vinelandii. Biochim. Biophys. Acta 20, 269-285 (1956). 

Synthesis of Polyribonucleotides. The synthesis of large polymers of ribose nucleotides is catalyzed by an enzyme named polynucleotide phosphorylase. This enzyme was first found in extracts of Azotobacter vinelandii, and similar preparations have been obtained in other bacteria. This type of enzyme has not yet been identified in animal tissues. 

The precise biological significance of polynucleotide phosphorylase is still unknown. It has been detected in several bacteria besides Azotobacter vinelandii, and in plant tissues, but not so far in animal tissues. It is likely to have a degradative rather than biosynthetic role. Highly purified preparations of the enzyme require an oligonucleotide to prime the reaction but the enzyme does not require or copy a template. After the isolation in 1960 of an E. coli enzyme (RNA polymerase) which synthesizes RNA upon directions from a DNA template, Ochoa isolated a similar enzyme from Azotobacter vinelandii and showed it to be distinct from polynucleotide phosphorylase. 

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See also in sourсe #XX -- [ , ]

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