Abstract
Soluble extracts of a neuroblastoma did not require additional methyl donor, S-adenosyl-L-methionine (SAM), for maximal catechol O-methltransferase activity. Prior dialysis of the extract resulted in complete loss of enzymatic activity which could be partially recovered by addition of SAM to the reaction mixture. Tritiated normetanephrine was formed from DL-norepinephrine-7-3H in the presence and absence of added SAM. Using ion exchange and thin layer chromatography a compound was isolated from a deproteinized extract of the tumor which migrated and reacted as authentic SAM in three different chromatographic solvent systems. Examination of tissue from a metastatic tumor in the same patient, obtained following radiation and chemotherapy, revealed similar catechol O-methyltransferase specific activity which was strictly dependent upon added SAM. No SAM was detectable in deproteinized extracts of this tissue. Urine from the patient did not contain detectable quantities of cystathionine, SAM, or S-adenosyl-L-homocysteine at any time. The urine did contain homocysteine as well as a prominent ninhydrin-positive spot which has not yet been identified. Demonstrable SAM in a neuroblastoma from a patient without cystathioninuria suggests that although methionine metabolizm may be active in the tumor the metabolites elaborated in the urine are not constant and presumably mirror variable enzymatic activities in the tumor. A difference can also be found between primary and metastatic tumor; an alteration possibly due to treatment.
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Lyon, G., Porter, F. S-Adenosyl-L-methionine in a Neuroblastoma. Pediatr Res 4, 454–455 (1970). https://doi.org/10.1203/00006450-197009000-00082
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DOI: https://doi.org/10.1203/00006450-197009000-00082