PURIFICATION AND KINETIC-PROPERTIES OF MUS BOODUGA (GRAY) HEPATIC ARGINASE

Hepatic L-arginase from the Mus booduga (Gray) was purified and its ki netic characteristics were investigated. The enzyme was not adsorbed o n DEAE-cellulose, but was retained on CM-cellulose column at pH 7.2. T he Michaelis-Menten constant was 8.3 mM for L-arginine and was indepen dent of pH in the range of 7.5-10.5. L-arginine concentrations as high as 0.4 M did not exert substrate inhibition in the pH range 7.4-10.0. Manganese was required at a concentration of 0.05 M for full activati on of the enyme. L-ornithine and L-lysine inhibited the enzyme competi tively with inhibitory constants of 1.9 mM and 3.7 mM respectively. Se veral properties of the L-arginase from Mus booduga clearly identify i t as an enzyme similar to ureotelic basic arginases from mammalian liv er.