STUDIES ON ARGINASE OF SCHISTOSOMA JAPONICUM
摘要
Adult worms of Schistosoma japonicum, collected from guinea pigs infected 31-54 days previously with 800 to 1,000 cercariae, were homogenized and the homogenate was incubated with 0.1M L-arginine (pH 9.0) at 37℃ for exactly 10 minutes. The urea thus formed was determined by the xanthydrol method and the arginase activity was expressed in micromoles of urea produced per mg. nitrogen of homogenate per hour. The average values of enzymatic activity for male, female and paired worms were 58.0±3.6, 67.2±18.3, and 55.6±10.7 respectively.The pH optimum for the enzyme was 9.0 and the maximal arginase activity was attained with the substrate concentration of 0.09 M.When the homogenate was pretreated with 10~(-3)M MnSO_4 or CoCl_2 for 30 minutes at 37℃, the enzymatic activity was increased 9.6 or 3.9 times respectively.Lysine, leucine as well as cucurbitine could inhibit this enzyme. F-30066, a new schistosomicide, also showed an inhibitory effect, which was increased considerably if the aqueous solution f F-30066 had been previously exposed to light. Such a solution of 2×10~(-5)M F-30066 caused 40% inhibition. In contrast, 10~(-4)M tartar emetic did not show any effect.The average urea content of Schistosoma japonicum was 1.4 microgram per mg. of nitrogen. Using 50-250 paired worms, no urease could be detected by the usual method.