| 摘要 |
The catalytic fragment (protein kinase M, PKM) of phosphatidylserinedependent
protein kinase (protein kinase C, PKC) has been shown to be associated with tumor formation. This fragment is referred to as “phospha tidy lserine-independen t protein kinase. ” These protein kinases were examined in breast and colorectal cancers. Both PKC and PKM were isolated by a DEAE-cellulose column chromatography; PKC was eluted in 120 mM KCl fractions while PKM in 300 mM KCl fractions. PKC activity increased in the breast cancer specimens (24.2±6.1 pmole32 P/min/mg) and decreased in the colorectal cancer specimens ( 28.9 ±7.4 pmole32 P/min/mg) when compared with that found in their corresponding, adjacent normal tissues (11.2±3.3 and 64.5±16.4 pmole32 P/min/mg, respectively). Elevated activity of PKM was detected in malignant breast and colorectal tissues (42.9±6.1 and 40.5±7.4 pmole32 P/min/mg, respectively) as compared with normal corresponding tissues (22.4±5.0 and 34.0 ±4.4 pmole32 P/min/mg, respectively). Furthermore, the 89-, 80－65-, 50- and 40-kilodalton (KDa) proteins were shown to increase predominantly in 300 mM KCl fractions from breast cancer tissues, whereas none of these proteins was detected in the normal corresponding tissues. These resu lts suggest that the activity of PKM may increase in both breast and colm.:ectal cancers, but PKC activity in these cancers ,seem to contradict ' each other. |
