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Angiotensin‐converting enzyme‐like activity in crab gills and its putative role in degradation of crustacean hyperglycemic hormone
Author(s) -
Chung J. Sook,
Webster S.G.
Publication year - 2008
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20247
Subject(s) - captopril , hemolymph , biology , carcinus maenas , hepatopancreas , gill , angiotensin converting enzyme , enzyme , biochemistry , substrate (aquarium) , crustacean , medicine , endocrinology , decapoda , ecology , fishery , fish <actinopterygii> , blood pressure
Angiotensin‐converting enzyme‐like enzyme activity (ACELA) was found in Carcinus maenas using reverse phase high performance liquid chromatography (RP‐HPLC) analysis of degradation kinetics of a synthetic substrate (Hippuryl‐histidyl‐leucine) and a specific inhibitor (captopril). Gills contained the highest ACELA, then brain, muscle, and testis, respectively, while no activity was detected in the following tissues: hepatopancreas, hindgut, hypodermis, heart, and hemolymph. ACELA present in gill membranes exhibited a K m of 0.23 mM and V max of 7.6 nmol with synthetic substrate. The enzyme activity was dependent on Cl – concentration and was markedly inhibited by captopril, lisinopril, and EDTA. Addition of Zn 2+ to membranes previously treated with EDTA restored 89% activity, suggesting that C. maenas ACELA is a Zn 2+ metalloenzyme. Gill membranes prepared from premolt crabs showed similar levels of ACELA to those of the intermolt animals. Administration of captopril in vivo lengthened the half life of circulating CHH, while in vitro incubation of gill membranes with captopril reduced CHH. These results suggest that C. maenas ACELA present in gills is likely to be involved in degradation of this neuropeptide. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley‐Liss, Inc..