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Carbonyl reductases from Daphnia are regulated by redox cycling compounds
Author(s) -
Ebert Bettina,
Ebert Dieter,
Koebsch Katrin,
Maser Edmund,
Kisiela Michael
Publication year - 2018
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14578
Subject(s) - oxidative stress , chemistry , menadione , biochemistry , methylglyoxal , reactive oxygen species , oxidative phosphorylation , enzyme
Oxidative stress is a major source of reactive carbonyl compounds that can damage cellular macromolecules, leading to so‐called carbonyl stress. Aside from endogenously formed carbonyls, including highly reactive short‐chain aldehydes and diketones, air pollutants derived from diesel exhaust like 9,10‐phenanthrenequinone ( PQ ) can amplify oxidative stress by redox cycling, causing tissue damage. Carbonyl reductases ( CR s), which are inducible in response to ROS , represent a fundamental enzymatic defense mechanism against oxidative stress. While commonly two carbonyl reductases ( CBR 1 and CBR 3) are found in mammalian genomes, invertebrate model organisms like Drosophila melanogaster express no CR but a functional homolog to human CBR 1, termed sniffer. The microcrustacean Daphnia is an ideal model organism to investigate the function of CR s because of its unique equipment with even four copies of the CR gene ( CR 1, CR 2, CR 3, CR 4) in addition to one sniffer gene. Cloning and catalytic characterization of two carbonyl reductases CR 1 and CR 3 from D. magna and D. pulex arenata revealed that both proteins reductively metabolize aromatic dicarbonyls (e.g., menadione, PQ ) and aliphatic α‐diketones (e.g., 2,3‐hexanedione), while sugar‐derived aldehydes (methylglyoxal, glyoxal) and lipid peroxidation products such as acrolein and butanal were poor substrates, indicating no physiological function in the metabolism of short‐chain aldehydes. Treatment of D. magna with redox cyclers like menadione and the pesticide paraquat led to an upregulation of CR 1 and CR 3 mRNA , suggesting a role in oxidative stress defense. Further studies are needed to investigate their potential to serve as novel biomarkers for oxidative stress in Daphnia .