Saponin
(0.2 mg mg1 protein) was routinely added to optimize substrate
accessibility. Briefly, about 100 mg each of gill filaments was
scrapped off from the gill arch or 100 mgof anterior portion of intestine,
or 100 mgof liver or kidney was homogenized in 2 ml of 0.25 M
SEI buffer (pH 7.1) and centrifuged at 700g for 10 min.