passages.id: split_5_test_3435_passage
passages.type: progene_text
passages.text: Moreover , when Asp405 was replaced with an Ala residue , the kcat / Km ratio was 1000 - fold lower than that of the wild - type ApB for hydrolysis of Arg-NA ; in contrast , in the hydrolysis of Tyr-NA , the kcat / Km ratios of the wild - type ( 1.1 x 10(4) M(-1) s(-1) ) and the mutated ( 8.2 x 10(3) M(-1) s(-1) ) enzymes were similar .