Ibsen K H, Basabe J R, Lopez T P
Cancer Res. 1975 Jan;35(1):180-8.
Isoelectrofocusing studies of mouse tissue extracts show mice to have a pyruvate kinase isozyme pattern very similar to that of the rat. Moreover, electrofocusing or kinetic assays conducted on liver extracts from normal mice and from mice bearing Ehrlich ascites tumors show that the latter have a higher proportion of the fetal K-isozyme of pyruvate kinase. Serial injection of the supernatant remaining after centrifugation of homogenized tumor cells at 100,000 x g, or of the phenolic extracts from the latter, produced a similar shift in the liver isozyme pattern involves both a decrease in L-isozyme activity and an increase in K-isozyme activity. However, only the increase in activity of the K-isozyme appears to be a specific response to injection of the extracts. The presence of a specific factor in these extracts was confirmed by the observation that similar extracts prepared from normal adult tissues did not increase activity of the K-isozyme. On the other hand, phenolic extracts from fetal mice did increase K-isozyme activity as did injections of serum from tumor-bearing mice or of the cell-free ascites fluid. Evidence is presented supporting the concept that the factor is proteinaceous in a nature, and that it acts by deprepressing synthesis of the K-isozyme.
对小鼠组织提取物的等电聚焦研究表明，小鼠的丙酮酸激酶同工酶模式与大鼠的非常相似。此外，对正常小鼠和携带艾氏腹水瘤小鼠的肝脏提取物进行的电聚焦或动力学分析表明，后者的丙酮酸激酶胎儿型K同工酶比例更高。对经100,000×g离心的匀浆肿瘤细胞上清液或其酚提取物进行连续注射，会使肝脏同工酶模式发生类似变化，包括L同工酶活性降低和K同工酶活性增加。然而，似乎只有K同工酶活性的增加是对提取物注射的特异性反应。通过观察从正常成年组织制备的类似提取物不会增加K同工酶活性，证实了这些提取物中存在特定因子。另一方面，来自胎鼠的酚提取物确实增加了K同工酶活性，携带肿瘤小鼠的血清注射或无细胞腹水液注射也有同样效果。有证据支持这样的观点，即该因子本质上是蛋白质，并且它通过解除对K同工酶合成的抑制作用来发挥作用。
