Mono-oxygenase activities of coho salmon (Oncorhynchus kisutch) liver microsomes using three polycyclic aromatic hydrocarbon substrates.

1. Benzo[a]pyrene, 2,6-dimethylnaphthalene, and naphthalene were used as substrates for a coho salmon (Oncorhynchus kisutch) liver microsomal preparation. 2. The apparent Michaelis constants (Km) were as follows: benzo[a]pyrene, 2.1 microM; 2,6-dimethylnaphthalene, 15.3 microM; and naphthalene, 300 microM. 3. The results indicate that the microsomal preparation had a high affinity for 2,6-dimethylnaphthalene. Thus, 2,6-dimethylnaphthalene, an important constituent of petroleum products, is a useful substrate for research on the disposition in vivo and in vitro of xenobiotics introduced into marine environments by petroleum pollution.