| Full text | |
| Author(s): |
Moraes, Cintya M.
[1]
;
Lucena, Malson N.
[2]
;
Garcon, Daniela P.
[3]
;
Pinto, Marcelo R.
[4]
;
Fabri, Leonardo M.
[1]
;
Faleiros, Rogerio O.
[5]
;
Fontes, Carlos F. L.
[6]
;
McNamar, John C.
[7, 8]
;
Leone, Francisco A.
[1]
Total Authors: 9
|
| Affiliation: | [1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Ave Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil
[2] Univ Fed Mato Grosso, Inst Biociencias, Campo Grande, MS - Brazil
[3] Univ Fed Triangulo Mineiro, Iturama, MG - Brazil
[4] Univ Uberaba, Lab Biopatol & Biol Mol, Uberaba, MG - Brazil
[5] Univ Fed Espirito Santo, Dept Ciencias Agr & Biol, Sao Mateus, ES - Brazil
[6] Univ Fed Rio de Janeiro, Inst Bioquim Med Leopoldo de Meis, Rio De Janeiro, RJ - Brazil
[7] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, Ribeirao Preto, SP - Brazil
[8] Univ Sao Paulo, Ctr Biol Marinha, Sao Sebastiao, SP - Brazil
Total Affiliations: 8
|
| Document type: | Journal article |
| Source: | Journal of Membrane Biology; v. 253, n. 3 MAY 2020. |
| Web of Science Citations: | 0 |
| Abstract | |
We provide a kinetic characterization of (Na+, K+)-ATPase activity in a posterior gill microsomal fraction from the grapsid crab Goniopsis cruentata. (Na+, K+)-ATPase activity constitutes 95% of total ATPase activity, and sucrose density centrifugation reveals an ATPase activity peak between 25 and 35% sucrose, distributed into two, partially separated protein fractions. The (Na+, K+)-ATPase alpha-subunit is localized throughout the ionocyte cytoplasm and has an M-r of approximate to 10 kDa and hydrolyzes ATP obeying cooperative kinetics. Low (V-M = 186.0 +/- 9.3 nmol Pi min(-1) mg(-1) protein and K-0.5 = 0.085 +/- 0.004 mmol L-1) and high (V-M = 153.4 +/- 7.7 nmol Pi min(-1) mg(-1) protein and K-0.5 = 0.013 +/- 0.0006 mmol L-1) affinity ATP binding sites were characterized. At low ATP concentrations, excess Mg2+ stimulates the enzyme, triggering exposure of a high-affinity binding site that accounts for 50% of (Na+, K+)-ATPase activity. Stimulation by Mg2+ (V-M = 425.9 +/- 25.5 nmol Pi min(-1) mg(-1) protein, K-0.5 = 0.16 +/- 0.01 mmol L-1), K+ (V-M = 485.3 +/- 24.3 nmol Pi min(-1) mg(-1) protein, K-0.5 = 0.9 +/- 0.05 mmol L-1), Na+ (V-M = 425.0 +/- 23.4 nmol Pi min(-1) mg(-1) protein, K-0.5 = 5.1 +/- 0.3 mmol L-1) and NH4+ (V-M = 497.9 +/- 24.9 nmol Pi min(-1) mg(-1) protein, K-0.5 = 9.7 +/- 0.5 mmol L-1) obeys cooperative kinetics. Ouabain inhibits up to 95% of ATPase activity with K-I = 196.6 +/- 9.8 mu mol L-1. This first kinetic characterization of the gill (Na+, K+)-ATPase in Goniopsis cruentata enables better comprehension of the biochemical underpinnings of osmoregulatory ability in this semi-terrestrial mangrove crab. {[}GRAPHICS] . (AU) | |
| FAPESP's process: | 16/25336-0 - Comparative biochemical study of gill (Na+, K +)- ATPase of Macrobrachium amazonicum (Heller, 1862) inhabitant of coastal and continental regions |
| Grantee: | Francisco de Assis Leone |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 13/24252-9 - The (Na+,K+)-ATPase in osmoregulatory capacity in crab Ucides cordatus: biochemical and molecular view |
| Grantee: | Malson Neilson de Lucena |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |