NAD(P)H-dependent epoxidation of aldrin in vitro by sea anemone microsomes

Previous studies from our laboratory indicated the presence of a functional P450-dependent mixed-function oxidase system (MFO) in the sea anemone (Phylum: Cnidaria). Further catalytic studies have demonstrated that sea anemone microsomes can metabolize aldrin to dieldrin through an epoxidation reaction in the presence of NAD(P)H. Based upon Nickel 63 ECD gas chromatography, dieldrin was the only metabolite detected. Further, the production of dieldrin was linear with time and protein concentration. Given the low levels of dieldrin produced, immediate and identical extractions were necessary to minimize variation among replicates. Under these conditions, activity was consistently observed in both Bunodosoma cavernata (NADH, 1.1–2.3; NADPH, 0.4–2.1 pmol/min/mg protein) and Anthopleura elegantissima (NADH, 0.5–2.9; NADPH, 0.3–4.5 pmol/min/mg protein). Only 60% of the A. xanthogrammica microsomal preparations were active (NADH, 0–1.0; NADPH, 0–1.5 pmol/min/mg protein). In B. cavernata and A. elegantissima, the rate of aldrin epoxidation was consistent with that observed in other marine invertebrates. [Supported in part by a grant from USDI/MMS.]