Cytochromes P450 in crustacea

Since the last review of this topic, further insight has been gained into t he presence and functions of cytochrome P450 proteins in the hepatopancreas and other organs of aquatic crustacean species, although progress has been slow relative to the advances in other species. Recent studies with severa l lobster, shrimp, crab and crayfish species suggest that cytochromes P450 in the 2 and 3 families are the most abundant forms in hepatopancreas micro somes. Substrates normally metabolized by CYP2 and CYP3 family members are monooxygenated more rapidly by crustacea than substrates normally metaboliz ed by CYP1 family enzymes, e.g. erythromycin, testosterone and aminopyrine are much more rapidly monooxygenated than ethoxyresorufin. Some progress ha s been made in cloning and sequencing crustacean P450 forms. CYP2L1 and CYP 2L2 cDNA sequences have been cloned from spiny lobster hepatopancreas libra ries, and there was evidence for at least two more cytochromes P450 in spin y lobster hepatopancreas. An area of continued interest, but of no consensu s or general findings, relates to the presence and inducibility of CYP1 fam ily members in crustacea; Some studies indicate weak induction of total cyt ochrome P450 and increased turnover of substrates normally associated with CYP1, while others show no effect of the classic inducers that act at the A h receptor in vertebrates. A few studies of the roles of cytochromes P450 i n the biosynthesis and degradation of steroids, including ecdysteroids, hav e been published. Further studies are needed to understand the regulation a nd normal function of the crustacean cytochromes P450. (C) 1998 Elsevier Sc ience Inc. All rights reserved.