TABLE 1

Catalytic activity of the AST IV mutants with 2-naphthol as substrate ^a

Step	Wild-Type	F77A	F138A	Y236A
		units/mg
Cell extract^b	39	0.6	0.6	3.7
PAP-Agarose	382	6.7	31	134
PD-10 gel filtration	515	13	40	348

↵ a Enzyme units are expressed as nanomoles of 2-naphthylsufate formed per minute, following assay with 250 μM 2-naphthol at pH 5.5
↵ b The extracts were obtained from 250 ml of bacterial cell culture grown to a wet weight of 3.5 g