Differential effects of cobalt ions in vitro on gill (Na+, K+)-ATPase kinetics in the Blue crab Callinectes danae (Decapoda, Brachyura).
Comp Biochem Physiol C Toxicol Pharmacol
; 274: 109757, 2023 Dec.
Article
em En
| MEDLINE
| ID: mdl-37741603
ABSTRACT
We used the gill (Na+, K+)-ATPase as a molecular marker to provide a comprehensive kinetic analysis of the effects of Co2+in vitro on the modulation of K+-phosphatase activity in the Blue crab Callinectes danae. Co2+ can stimulate or inhibit K+-phosphatase activity. With Mg2+, K+-phosphatase activity is almost completely inhibited by Co2+. Co2+ stimulates K+-phosphatase activity similarly to Mg2+ although with a ≈4.5-fold greater affinity. At saturating Mg2+ concentrations, Mg2+ displaces bound Co2+ from the Mg2+-binding site in a concentration dependent manner, but Co2+ cannot displace Mg2+ from its binding site even at millimolar concentrations. Saturation by Co2+ of the Mg2+ binding site does not affect pNPP recognition by the enzyme. Substitution of Mg2+ by Co2+ slightly increases enzyme affinity for K+ and NH4+. Independently of Mg2+, inhibition by ouabain or sodium ions is unaffected by Co2+. Investigation of gill (Na+, K+)-ATPase K+-phosphatase activity provides a reliable tool to examine the kinetic effects of Co2+ with and without Na+ and ATP. Given that the toxic effects of Co2+ at the molecular level are poorly understood, these findings advance our knowledge of the mechanism of action of Co2+ on the crustacean gill (Na+, K+)-ATPase.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Braquiúros
Limite:
Animals
Idioma:
En
Revista:
Comp Biochem Physiol C Toxicol Pharmacol
Ano de publicação:
2023
Tipo de documento:
Article