title: Polyamines regulate phosphorylation-dephosphorylation kinetics in a crustacean gill (Na+, K+)-ATPase.
abstract: Aiming to clarify the mechanism of inhibition of (Na+, K+)-ATPase activity by polyamines, we examined the effects of exogenous putrescine, spermidine, and spermine on the kinetic behavior of phosphoenzyme-linked partial reactions using a microsomal gill (Na+, K+)-ATPase from juvenile and adult M. amazonicum, a freshwater palaemonid shrimp. The time course of phosphointermediate formation is greater (0.089 ± 0.006 s-1) in adults than in juveniles (0.053 ± 0.003 s-1) for spermidine, but similar to juveniles (0.059 ± 0.004 s-1) for putrescine. Maximum phosphointermediate formation for the (Na+, K+)-ATPase from juveniles decreased by 46% and 32% with spermidine and putrescine, respectively. In adults, maximum phosphointermediate levels decreased by 50% and 8%, respectively. For both spermidine and putrescine, dephosphorylation rates were higher for adults than for juveniles, and were higher than in controls without polyamines. Spermine had a negligible effect (<10%) on phosphorylation/dephosphorylation rates of both juvenile and adult enzymes. This is the first report on the effects of polyamines on phosphoenzyme-linked partial reactions in juvenile and adult M. amazonicum gill (Na+, K+)-ATPases. Our findings suggest that the phosphorylation/dephosphorylation steps of this gill enzyme may be regulated by polyamines during ontogenetic development.
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, 14040-901, Brazil.
authors.forename: Malson Neilson
authors.initials: MN
authors.lastname: Lucena
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, 14040-901, Brazil.|Universidade Federal do Triângulo Mineiro, Campus Universitário de Iturama, Iturama, Minas Gerais, 38280-000, Brazil.
authors.forename: Daniela Pereira
authors.initials: DP
authors.lastname: Garçon
authors.affiliation: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Carlos Frederico Leite
authors.initials: CF
authors.lastname: Fontes
authors.affiliation: Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, SP, Brazil.|Centro de Biologia Marinha, Universidade de São Paulo, São Sebastião, SP, Brazil.
authors.forename: John Campbell
authors.initials: JC
authors.lastname: McNamara
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, 14040-901, Brazil. fdaleone@ffclrp.usp.br.
authors.forename: Francisco Assis
authors.initials: FA
authors.lastname: Leone
mesh_terms: D000818:Animals; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005880:Gills / Q000187:drug effects / Q000201:enzymology*; D007700:Kinetics; D033541:Palaemonidae / Q000187:drug effects / Q000201:enzymology*; D010766:Phosphorylation / Q000187:drug effects; D011073:Polyamines / Q000494:pharmacology*; D011700:Putrescine / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013095:Spermidine / Q000494:pharmacology; D013096:Spermine / Q000494:pharmacology
chemical_list: D011073:Polyamines; D013096:Spermine; D000254:Sodium-Potassium-Exchanging ATPase; D013095:Spermidine; D011700:Putrescine
keywords: (Na+, K+)-ATPase; Dephosphorylation; Freshwater shrimp, Macrobrachium amazonicum; Ontogenetic stage; Phosphorylation; Polyamines