Autor(es)

Leone, Francisco A. ; Fabri, Leonardo M. ; Costa, Maria I. C. ; Moraes, Cintya M. ; Garcon, Daniela P. ; McNamara, John C.

• Tipo de documento: Artigo Científico
• Fonte: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY; v. 274, p. 11-pg., 2023-09-28.

Resumo

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 approximate to 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. (AU)

• Processo FAPESP: 16/25336-0 - Estudo bioquímico comparativo da (Na+, K+)-ATPase branquial de Macrobrachium amazonicum (Heller, 1862) habitantes de regiões costeiras e continentais
• Beneficiário: Francisco de Assis Leone
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 19/21899-8 - Caracterização cinética e molecular da (Na+, K+)-ATPase branquial de Macrobrachium amazonicum (Heller, 1862) habitantes do Pantanal Matogrossense e da Bacia dos Rios Tocantins-Araguaia
• Beneficiário: Francisco de Assis Leone
• Modalidade de apoio: Auxílio à Pesquisa - Regular