Angiotensin‐converting enzyme‐like activity in crab gills and its putative role in degradation of crustacean hyperglycemic hormone

Abstract

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 Zn2+ to membranes previously treated with EDTA restored 89% activity, suggesting that C. maenas ACELA is a Zn2+ 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.

A second copper zinc superoxide dismutase (CuZnSOD) in the blue crab Callinectes sapidus: Cloning and up-regulated expression in the hemocytes after immune challenge

“…Juvenile animals were reared under the following conditions (15e18 parts per thousand at 22 C) to carapace width of 70e90 mm as reported [24]. Animals at intermolt stage [25] were used for immune challenges with LPS and LTA.…”

Control of aging by the renin–angiotensin system: a review of C. elegans, Drosophila, and mammals

“…It is well established that ACE is an essential enzyme in many organisms; the knockout of ACE or its homologs in other species has severe negative effects on health in mammals and is lethal in Drosophila and C. elegans (Tatei et al, 1995;Esther et al, 1996;Brooks et al, 2003;Kumar et al, 2016;Nichols et al, 2016). ACE likely evolved in a hypothesized most recent common ancestor of the Bilaterian clade; since that time functional ACE homologs have been retained in such diverse phyla as insects (Lamango and Isaac, 1994;Cornell et al, 1995;Wijffels et al, 1996;Wijffels et al, 1997;Loeb et al, 1998;Isaac et al, 1999;Vandingenen et al, 2001;Vandingenen et al, 2002;Ekbote et al, 2003a;Ekbote et al, 2003b;Nathalie et al, 2003;Burnham et al, 2005;Lemeire et al, 2008;Wang et al, 2015;Abu Hasan et al, 2017;Nagaoka et al, 2017;Wang et al, 2019), crustaceans (Smiley and Doig, 1994;Kamech et al, 2007;Sook Chung and Webster, 2008), mollusks (Laurent et al, 1997;Riviere et al, 2011), annelids (Rivière et al, 2004), nematodes (Brooks et al, 2003;Kumar et al, 2016;Metheetrairut et al, 2017;Kucuktepe, 2021), and vertebrates (reviewed in (Lv et al, 2018)). Metalloprotease activity, predicted by the highly conserved histidine-rich HEXXH motif, is retained in all known organisms with an active ACE other than nematode ACN-1, indicating a high degree of evolutionary selective pressure to retain this motif.…”

“…ACE inhibitors bind to and competitively inhibit this active site, and ACE inhibitors have been shown to function in non-vertebrate animals (Lamango and Isaac, 1994;Smiley and Doig, 1994;Wijffels et al, 1996;Wijffels et al, 1997;Isaac et al, 1999;Vandingenen et al, 2001;Vandingenen et al, 2002;Ekbote et al, 2003a;Ekbote et al, 2003b;Nathalie et al, 2003;Rivière et al, 2004;Vercruysse et al, 2004;Kamech et al, 2007;Lemeire et al, 2008;Sook Chung and Webster, 2008;Nagaoka et al, 2017). ACE has been shown to be involved in fertility in mice, Drosophila, and other arthropods (Wijffels et al, 1996;Wijffels et al, 1997;Loeb et al, 1998;Ramaraj et al, 1998;Isaac et al, 1999;Vandingenen et al, 2002;Ekbote et al, 2003a;Ekbote et al, 2003b;Hurst et al, 2003;Nathalie et al, 2003;Vercruysse et al, 2004;Kamech et al, 2007;Sook Chung and Webster, 2008;Riviere et al, 2011;Nagaoka et al, 2017), being commonly expressed in the testis or ovaries, and effecting sperm motility or progeny production in many species. This is especially interesting considering the existence of a testis-specific isoform of ACE in mammals, called tACE; this isoform has been shown to regulate male fertility and sperm function (Hagaman et al, 1998).…”

Characterization of a membrane‐bound angiotensin‐converting enzyme isoform in crayfish testis and evidence for its release into the seminal fluid

“…2). Accordingly, an ACE‐like activity was reported in the membranes of C. maenas gills, which may be easily solubilized by detergent application [20]. At present, it is not possible to speculate whether, in crustaceans, in contrast to other groups, ACE isoforms are always membrane‐bound proteins because no genome has been sequenced from a crustacean species other than Daphnia .…”