An enzymatic radioactive assay to determine ribose 1-phosphate in tissues

Ribose 1-phosphate has been measured in rat tissues by an enzymatic radioactive assay. The sugar phosphate is converted into [14C]inosine via the two following combined reactions: ribose 1-phosphate + [14C]adenine ⇌ [14C]adenosine + phosphate (adenosine phosphorylase); [14C]adenosine + H2O → [14C]inosine + NH3 (adenosine deaminase). Tissue extracts are incubated in the presence of excess [14C]adenine. The radioactivity of inosine, separated by a thin-layer chromatographic system, is a measure of ribose 1-phosphate present in tissue extracts. Liver was found to contain the highest level of ribose 1-phosphate (ca. 800 nmol/g wet wt).