Kinetic characterization of the gill (Na+, K+)-ATPase in a hololimnetic population of the diadromous Amazon River shrimp Macrobrachium amazonicum (Decapoda, Palaemonidae).
Comp Biochem Physiol B Biochem Mol Biol
; 227: 64-74, 2019 Jan.
Article
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| MEDLINE
| ID: mdl-30267892
ABSTRACT
We provide a kinetic characterization of (Na+, K+)-ATPase activity in a posterior gill microsomal fraction from a hololimnetic population of the diadromous Amazon River shrimp Macrobrachium amazonicum. Sucrose density gradient centrifugation reveals two distinct membrane fractions showing considerable (Na+, K+)ATP-ase activity, but also containing other microsomal ATPases. Only a single immune-reactive (Na+, K+)-ATPase with Mr of ≈110â¯kDa is present that hydrolyzes ATP with VMâ¯=â¯130.3⯱â¯4.8â¯nmol Pi min-1 mg protein-1 and K0.5â¯=â¯0.065⯱â¯0.00162â¯mmolâ¯L-1, exhibiting site-site interactions. Stimulation by Na+ (VMâ¯=â¯127.5⯱â¯5.3â¯nmol Pi min-1 mg protein-1, K0.5â¯=â¯5.3⯱â¯0.42â¯mmolâ¯L-1), Mg2+ (VMâ¯=â¯130.6⯱â¯6.8â¯nmol Pi min-1 mg protein-1, K0.5â¯=â¯0.33⯱â¯0.042â¯mmolâ¯L-1), K+ (VMâ¯=â¯126.7⯱â¯7.7â¯nmol Pi min-1 mg protein-1, K0.5â¯=â¯0.65⯱â¯0.0079â¯mmolâ¯L-1) and NH4+ (VMâ¯=â¯134.5⯱â¯8.6â¯nmol Pi min-1 mg protein-1, K0.5â¯=â¯1.28⯱â¯0.44â¯mmolâ¯L-1) also obeys cooperative kinetics. Ouabain (KIâ¯=â¯0.18⯱â¯0.058â¯mmolâ¯L-1) inhibits total ATPase activity by ≈70%. This study reveals considerable differences in the kinetic characteristics of the gill (Na+, K+)-ATPase in a hololimnetic population that appear to result from the adaptation of diadromous Macrobrachium amazonicum populations to different limnic habitats.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
ATPasa Intercambiadora de Sodio-Potasio
/
Palaemonidae
/
Proteínas de Artrópodos
/
Microsomas
Límite:
Animals
País/Región como asunto:
America do sul
/
Brasil
Idioma:
En
Revista:
Comp Biochem Physiol B Biochem Mol Biol
Asunto de la revista:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
Año:
2019
Tipo del documento:
Article
País de afiliación:
Brasil