Occurrence of Inosine Kinase as a Distinct Enzyme in Spirulina platensis

• Published in: Biochemical and biophysical research communications Vol. 209; no. 2; pp. 547 - 553
• Main Authors: Ipata, P.L., Gualerzi, C., Scolozzi, C., Tozzi, M.G., Trinei, M., Barsacchi, D.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 17-04-1995
• Subjects: Cyanobacteria - enzymology; Electrophoresis; Inosine Monophosphate - metabolism; Phosphotransferases (Alcohol Group Acceptor) - chemistry; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Purines - metabolism
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1995.1536

Among a series of purine nucleosides, inosine was found to be phosphorylated at the highest rate by crude extracts of the cyanobacterium Spirulina platensis. The inosine phosphorylating activity could be separated from hypoxanthine-guanine phosphoribosyl transferase. This result shows that IMP formation may occur via the direct phosphorylation of inosine at its 5′-position, rather than via inosine phosphorolysis, followed by hypoxanthine phosphoribosylation, and provides unequivocal evidence for the occurrence of inosine kinase in nature.