Avtor/Urednik     Delneri, A; Franca, R; Terdoslavich, M; Montanič, S; Čurin-Šerbec, V; Tramer, F; Francese, M; Passamonti, S
Naslov     Identification and functional characterization of bilitranslocase in sea-bass (Dicentrarchus labrax) hepatopancreas
Tip     članek
Vir     Analytical letters
Vol. in št.     Letnik 44, št. 18
Leto izdaje     2011
Obseg     str. 2887-2900
Jezik     eng
Abstrakt     The mammalian bilirubin transporter bilitranslocase (BTL, T.C.#2.A.65.1.1) is found in both absorptive (intestine) and excretory epithelia (liver, kidney) and in the vascular endothelium. The aim of this work was to investigate whether a BTL homologue is expressed also in fish hepatopancreas. Immunochemistry based on an antisequence antibody specific for rat liver BTL demonstrated the presence of such homologue in sea-bass (Dicentrarchus labrax) hepatopancreas. Furthermore the transport activity of such a carrier, measured as electrogenic bromosulphophthalein (BSP) uptake, was assayed in sea-bass microsomes, where it was inhibited by the same antibody. Transport activity in fish showed numerous kinetic similarities with rat, such as BSP Km(about 5 microM in both), bilirubin Ki (about 0.1 microM), quercetin competitive Ki (about 20 microM), and noncompetitive Ki (about 85 microM). Biliverdin Ki was instead nearly 10-fold higher in fish than in rat (0.97 ± 0.06 microM and 0.11 ± 0.01 microM, respectively). Fish BTL was found to exist in two different allosteric forms with different affinities for the substrate, similarly to rat liver BTL. It was found that sea-bass BTL is very sensitive to inhibition by HgCl2, a major water pollutant, making it reasonable to exploit fish BTL activity as an ecotoxicological biosensor.
Deskriptorji     FISHES
LIVER
PANCREAS
PEPTIDYL TRANSFERASES
BILIRUBIN
BIOLOGICAL TRANSPORT
MICROSOMES
MERCURY
IMMUNOBLOTTING
AQUACULTURE