EVIDENCE AGAINST EXISTENCE OF GUANOSINE AND INOSINE KINASES IN HUMAN FIBROBLASTS IN TISSUE CULTURE

Human HGPRT- cells derived from patients with the Lesch-Nyhan syndrome have been labeled with 3H-hypoxanthine, 3H-guanosine and 3H-inosine in an effort to demonstrate inosine kinase or guanosine kinase activity. HGPRT- fibroblasts showed virtually no incorporation of any of these labeled nucleic acid precursors into TCA insoluble material when the cells were examined by autoradiographic techniques. We interpret these results as indicating either that these tissue culture cells have no detectable inosine kinase or guanosine kinase activity or that although the kinases are present they are also inactive due to a defect in a polypeptide subunit or ligand common to HGPRT and the kinases. © 1969.