title: Increased thymidylate synthase (EC 2.1.1.45) activity in normal and neoplastic proliferation.
abstract: Thymidylate (dTMP) synthase (EC 2.1.1.45) activity was measured in 100,000 x g supernatant fluid with a sensitive, rapid radio assay. The activity in normal rat liver was low (0.098-0.204 nmol/hr/mg protein). dTMP synthase specific activities in rat thymus, spleen, bone marrow, testis, lung, heart, brain, kidney, and small intestine were 6297, 1842, 1500, 788, 215, 76, 61, 39 and 24%, respectively, of that of the liver. The activity in 5-day-old rat liver was 16-fold higher than in adult. dTMP synthase activity increased in rat hepatomas to 7- to 125-fold of that of normal rat liver. There was a significant correlation between the increase in synthase activity and the proliferation rates of the hepatomas. In 8 human colon carcinomas, dTMP synthase activity increased to 2.9- to 8-fold of that of normal human colon mucosa. In leukemic leukocytes from 3 leukemia patients, activity was 8- to 10-fold higher than in normal leukocytes.
authors.affiliation: Laboratory for Experimental Oncology, Indiana University School of Medicine, Indianapolis 46223.
authors.forename: Y
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Shiotani
authors.forename: J N
authors.initials: JN
authors.lastname: Eble
authors.forename: J L
authors.initials: JL
authors.lastname: Glover
authors.forename: G
authors.initials: G
authors.lastname: Weber
mesh_terms: D000375:Aging; D000818:Animals; D002471:Cell Transformation, Neoplastic; D003106:Colon / Q000201:enzymology; D003110:Colonic Neoplasms / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology; D007700:Kinetics; D007938:Leukemia / Q000201:enzymology; D007962:Leukocytes / Q000201:enzymology; D008099:Liver / Q000201:enzymology* / Q000254:growth & development; D008114:Liver Neoplasms, Experimental / Q000201:enzymology*; D008297:Male; D009928:Organ Specificity; D051381:Rats; D012016:Reference Values; D013940:Thymidylate Synthase / Q000378:metabolism*
chemical_list: D013940:Thymidylate Synthase