Al protein methylase I(Al PMI) activity has been well known to increase in highly
proliferative cells, intracellular substrate of which, 20 kDa protein, has been discovered
recently. Present study intended to investigate the relevance of ovarian cancer
development and arginine methylation of the protein, comparing the intensities of 20 kDa
protein and Al protein arginine methylation in normal ovary and ovarian cancer tissues.
Normal ovary and ovarian cancer tissues were taken from the same ovarian cancer
patient. Al protein expression was induced 30-40 fold by IPTG in BL2l (DES3) LysS
E-coli, and Al protein was purified to apparent homogeneity with an yield of 2.89mg per
g E-coli. Specific activities of Al PMI in normal and cancer ovarian tissues were 0.17,
0.2, 1.18 fold higher in cancer tissue for intracellular substrates, and 5.6, 7.0, 1.25 fold
higher in cancer tissue for Al protein. Fluorography revealed methylated 20 kDa protein
as an only intracellular substrate of Al PMI, the intensities of which for normal and
cancer ovarian tissues corresponded to enzyme activity measurements. When Al protein
was added as exogenous substrates, methylated Al was observed, which parelled the
enzyme activities in applied samples, and 20 kDa protein was found to disappear.
Conclusively, it was confirmed that 20 kDa protein is the most favored intracellular
substrate for A1PMI in physiologic condition, and the protein and Al protein are
methylated by the same enzyme competitively.
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