Tisdale M J
Cancer Biochem Biophys. 1984 Jun;7(2):101-7.
Tumors of peripheral tissues contain low levels of succinyl CoA-acetoacetate CoA transferase activity which is not induced in vitro by prolonged cultivation in 2.5 mM DL-3-hydroxybutyrate. Although this enzyme is considered to be the main agent controlling the extent to which ketone bodies serve as metabolic substrates such tumors metabolize D(-)-3-hydroxy[3(14)C]butyrate to 14CO2. Also addition of 3-hydroxybutyrate and/or acetoacetate reduces the amount of 14CO2 produced from D-[U-14C] glucose suggesting a common metabolic intermediate. These observations can be accounted for by the presence of acetoacetyl-CoA synthetase, an enzyme which is able to synthesize acetoacetyl-CoA directly from acetoacetate, ATP and coenzyme A. This is the first demonstration of this enzyme in tumor tissue. The rate of metabolism of acetoacetate by this enzyme is sufficient to account for the production of CO2 from 3-hydroxybutyrate.
外周组织肿瘤中琥珀酰辅酶A - 乙酰乙酸辅酶A转移酶活性水平较低，在2.5 mM DL - 3 - 羟基丁酸中长时间体外培养也不会诱导该酶活性。尽管这种酶被认为是控制酮体作为代谢底物程度的主要因素，但此类肿瘤仍能将D(-)-3 - 羟基[3(14)C]丁酸代谢为14CO2。此外，添加3 - 羟基丁酸和/或乙酰乙酸会减少D - [U - 14C]葡萄糖产生的14CO2量，这表明存在一种共同的代谢中间体。这些观察结果可以通过乙酰乙酰辅酶A合成酶的存在来解释，该酶能够直接从乙酰乙酸、ATP和辅酶A合成乙酰乙酰辅酶A。这是该酶在肿瘤组织中的首次证明。该酶代谢乙酰乙酸的速率足以解释3 - 羟基丁酸产生CO2的过程。
