Abstract
The inorganic Pyrophosphatase activities of sera from human and rat were assayed as substrate 3.0mM sodium pyrophosphatase in 50mM Tris-HCl-1mM MgCl2, pH 8.5.
The result of this work was reported in the 42nd Congress of the Japanese Orthopedic Association in April, 1969.
In the present paper, the inhibitions of pyrophosphatase activity by heat, urea and EDTA-2Na were examined with reference to alkalne phosphatase activity, employing the homogenates of human tissue extracts as the crude enzyme solution. Heat inactivation: the enzyme solution with MgCl2 and H2O was incubated for 5, 10, 15min. at 56°C. After 3min. cooling in ice bath, the remaining activity was assayed. Effects of urea and EDTA: the enzyme solution was preincubated with urea or EDTA-2Na of various concentration for 15min. at 37°C, and then activity was assayed. The results;
The pyrophosphatase activities in both patient serum and tissue extracts were parallel with those of alkaline phosphatase.
The alkaline phosphatase/pyrophosphatase ratios of itssue extracts were 7 to 9 except for intestine extract. In heat inactivation and effect of urea, pyrophosphatase activities of placental extract and serum of pregnant woman were most stable, whereas those of bone extract and serum of skeletal disease were extremely inactivated.
As compared with alkaline phosphatase, pyrophosphatase activity was more stable by heating and more inhibited by EDTA treatment. The result shows that the increased activity of inorganic pyrophosphatase in serum of bone diseases acts as a marker of bone metabolism.
