Bacterial Enzymes Acting on Nucleosides and Nucleotides

Bacterial extracts have been shown to contain enzymes which act on nucleosides and nucleotides. In some cases, these enzymes are useful for the preparation of such substances, and, in the following Section, a survey of the more important reactions is given. 

Extracts of certain bacteria requiring 2-deoxyribonucleosides, namely, Lactobacillus helveticus, Lactobacillus delbriickii, and Thermobacterium acidophilus R 26, catalyze the transfer of the 2-deoxy-D-ribosyl group from one purine or pyrimidine to another. 2-Deoxyribosyl -uracil, thy- 

A transribosylase which exchanges the hypoxanthine of inosine with adenine, guanine, xanthine, thymidine, 4,5-diaminouracil, 5-bromouracil, and 4,6-diaminouracil has been found in Escherichia coli. -  

Phosphorolysis of ribosylpurines, 2-deoxy-D-ribosyl -purines, uridine, and thymidine has been detected in a number of bacteria.  

A phosphorylase from Escherichia coli has been purified it is specific for 2-deoxy-D-ribosyl phosphate, but can use uracil, 2-thiouracil, 5-amino-uracil, 5-bromouracil, and 2-thiothymine as a pyrimidine. Deaminases of adenosine, 2-deoxyadenosine, cytidine, and 2-deoxycytidine have been detected in Escherichia coli. 

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