Components of the cytochrome P450-dependent monooxygenase system and 'NADPH-independent benzo[a]pyrene hydroxylase' activity in a wide range of marine invertebrate species.
Levels of components of the cytochrome P450 (CYP)-dependent monooxygenase system were characterised in microsomes of major biotransformation tissues, or whole bodies, of 33 species from six phyla of aquatic invertebrates. The phylogenetic distribution of benzo[a]pyrene hydroxylase (BPH) activity in the absence of added NADPH (so-called 'NADPH-independent BPH activity') and presence of NADPH was also examined. Microsomal protein yield was higher in individual tissues than whole tissues. The main components (total CYP and cytochrome b5; NADPH-dependent cytochrome c (CYP) reductase, NADH-dependent cytochrome c reductase and NADH-dependent ferricyanide (b5) reductase activities) were found in most species of the Porifera, Cnidaria, Mollusca, Polychaeta, Crustacea and Echinodermata examined. The so-called '418-peak' of the carbon-monoxide difference spectrum of reduced microsomes was found in all species, indicating the wide distribution of this protein. Total CYP levels (pmol mg(-1) protein; mean+/-SEM) were similar in molluscs (50+/-7), crustaceans (61+/-11) and echinoderms (56+/-9), with the exception of high levels (223-266) in two crustacean species. NADPH-dependent BPH activity (pmol min(-1) mg(-1) protein) was found in 32 species, being lowest in Porifera and Cnidaria (3-4), intermediate in Mollusca (7.8+/-1.3), and highest in Crustacea (25+/-4) and Echinodermata (15+/-4). NADPH-independent BPH activity was evident in 13 out of 15 molluscan species examined, with the addition of NADPH either stimulating (8 species) or inhibiting (5 species) the activity. NADPH-independent BPH activity was also seen in two poriferan species and indicated in three crustacean species, suggesting that the phenomenon is not solely restricted to the Mollusca.
Environmental Chemistry Department, IIQAB-CSIC, Jordi Girona, 18-26, 08034 Barcelona, Spain. msole@icm.csic.es
Montserrat
M
Solé
David R
DR
Livingstone
D000818:Animals; D001579:Benzopyrene Hydroxylase / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D015786:Cytochromes b5 / Q000378:metabolism; D005420:Flavoproteins / Q000378:metabolism; D007448:Invertebrates / Q000201:enzymology* / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008861:Microsomes / Q000201:enzymology; D009249:NADP / Q000378:metabolism; D009792:Oceans and Seas; D010088:Oxidoreductases / Q000378:metabolism
D005420:Flavoproteins; D009249:NADP; D015786:Cytochromes b5; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D001579:Benzopyrene Hydroxylase