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.
Solé
Montserrat
M
Environmental Chemistry Department, IIQAB-CSIC, Jordi Girona, 18-26, 08034 Barcelona, Spain. msole@icm.csic.es
Livingstone
David R
DR
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