Adenine Formation from Adenosine by Mycoplasmas: Adenosine Phosphorylase Activity

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 72; no. 4; pp. 1401 - 1405
• Main Authors: Hatanaka, Masakazu, Del Giudice, Richard, Long, Cedric
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01.04.1975; National Acad Sciences
• Subjects: Acholeplasma laidlawii - enzymology; Adenine - biosynthesis; Adenosine - metabolism; Animal cells; Animals; Cell culture techniques; Cell Line; Cells, Cultured; Cricetinae; Cultured cells; Enzymes; Humans; Hypoxia; Ice; Kinetics; Mice; Mycoplasma; Mycoplasma - enzymology; Mycoplasmatales; Pentosyltransferases - metabolism; Phosphates; Radioactive decay; Species Specificity; Time Factors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.72.4.1401

Mammalian cells have enzymes to convert adenosine to inosine by deamination and inosine to hypoxanthine by phosphorolysis, but they do not possess the enzymes necessary to form the free base, adenine, from adenosine. Mycoplasmas grown in broth or in cell cultures can produce adenine from adenosine. This activity was detected in a variety of mycoplasmatales, and the enzyme was shown to be adenosine phosphorylase. Adenosine formation from adenine and ribose 1-phosphate, the reverse reaction of adenine formation from adenosine, was also observed with the mycoplasma enzyme. Adenosine phosphorylase is apparently common to the mycoplasmatales but it is not universal, and the organisms can be divided into three groups on the basis of their use of adenosine as substrate. Thirteen of 16 Mycoplasma, Acholeplasma, and Spiroplasma species tested exhibit adenosine phosphorylase activity. M. lipophilium differed from the other mycoplasmas and shared with mammalian cells the ability to convert adenosine to inosine by deamination. M. pneumoniae and the unclassified M. sp. 70-159 showed no reaction with adenosine. Adenosine phosphorylase activity offers an additional method for the detection of mycoplasma contamination of cells. The patterns of nucleoside metabolism will provide additional characteristics for identification of mycoplasmas and also may provide new insight into the classification of mycoplasmas.