Abstract
Human urinary arginine esterase-2 (HUAE-2) was purified to homogeneity mainly by chromatographic methods. About 2950-fold purification was achieved, with yield of 30% of the initial N-α-tosyl-L-arginine methyl ester (Tos-Arg-Me) hydrolyzing activity. The specific activity of the finally purified HUAE-2 was 2.07 μmol/min/A280 for Tos-Arg-Me. The esterolytic and amidolytic actions of this enzyme showed broad specificities for arginine and lysine derivatives as substrates, and the substrate specificity of this enzyme was clearly different from that of partially purified human urinary arginine esterase-1 (HUAE-1). Aprotinin strongly suppressed the Val-Leu-Arg-pNA amidolytic activity of HUAE-2, while ovomucoid trypsin inhibitor and lima bean trypsin inhibitor were less effective. The isoelectric point (pI value) and optimum pH of this enzyme were determined to be pI 4.5 and pH 8.5, respectively.
