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Malignant transformation‐linked imbalance: Decreased xanthine oxidase activity in hepatomas
Author(s) -
Prajda Noemi,
Weber George
Publication year - 1975
Publication title -
febs letters
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(75)80385-1
Subject(s) - xanthine oxidase , chemistry , transformation (genetics) , biochemistry , malignant transformation , xanthine , medicine , endocrinology , cancer research , enzyme , biology , gene
Xanthine oxidase was decreased 2- to 10-fold in all examined rat hepatomas irrespective of the malignancy; growth rate and degrees of histological differentiation of the neoplasms. The affinity to substrate (KM=6-8 muM) and the pH optimum (8.0) of the liver and hepatoma enzymes were the same. The reprogramming of gene expression, as manifested in the decreased activity of this key purine metabolizing enzyme, appears to be specific to neoplastic transformation. Since glutamine PRPP amidotransferase activity was increased but the opposing enzyme, xanthine oxidase, was decreased in all the hepatomas, the reprogramming of gene expression results in an imbalance that favors synthesis against catabolism. This enzymatic imbalance should confer selective advantages to the cancer cells.