Biomaterial Database

An endogenous factor which interacts with synaptosomal membrane Na+, K(+)-ATPase activation by K+. 1993

G Rodríguez de Lores Arnaiz

Instituto de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Argentina.

In previous papers, the isolation of brain soluble fractions able to modify neuronal Na+, K(+)-ATPase activity has been described. One of those fractions-peak I-stimulates membrane Na+, K(+)-ATPase while another-peak II-inhibits this enzyme activity, and has other ouabain-like properties. In the present study, synaptosomal membrane Na+, K(+)-ATPase was analyzed under several experimental conditions, using ATP or p-nitrophenylphosphate (p-NPP) as substrate, in the absence and presence of cerebral cortex peak II. Peak II inhibited K(+)-p-NPPase activity in a concentration dependent manner. Double reciprocal plots indicated that peak II uncompetitively inhibits K(+)-p-NPPase activity regarding substrate, Mg2+ and K+ concentration. Peak II failed to block the known K(+)-p-NPPase stimulation caused by ATP plus Na+. At various K+ concentrations, percentage K(+)-p-NPPase inhibition by peak II was similar regardless of the ATP plus Na+ presence, indicating lack of correlation with enzyme phosphorylation. Na+, K(+)-ATPase activity was decreased by peak II depending on K+ concentration. It is postulated that the inhibitory factor(s) present in peak II interfere(s) with enzyme activation by K+.

UI	MeSH Term	Description	Entries
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D008297	Male		Males
D009597	4-Nitrophenylphosphatase	An enzyme that catalyzes the hydrolysis of nitrophenyl phosphates to nitrophenols. At acid pH it is probably ACID PHOSPHATASE (EC 3.1.3.2); at alkaline pH it is probably ALKALINE PHOSPHATASE (EC 3.1.3.1). EC 3.1.3.41.	4-Nitrophenyl Phosphatase,K+-NPPase,K-Dependent p-Nitrophenylphosphatase,K-p NPPase,Nitrophenyl Phosphatase,p-NPPase,p-Nitrophenylphosphatase,para-Nitrophenyl Phosphatase,para-Nitrophenylphosphatase,4 Nitrophenyl Phosphatase,4 Nitrophenylphosphatase,K Dependent p Nitrophenylphosphatase,K p NPPase,K+ NPPase,p NPPase,p Nitrophenylphosphatase,p-Nitrophenylphosphatase, K-Dependent,para Nitrophenyl Phosphatase,para Nitrophenylphosphatase
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005260	Female		Females
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001685	Biological Factors	Endogenously synthesized compounds that influence biological processes not otherwise classified under ENZYMES; HORMONES or HORMONE ANTAGONISTS.	Biologic Factors,Biological Factor,Factor, Biologic,Factor, Biological,Factors, Biological,Biologic Factor,Factors, Biologic
D013574	Synaptosomes	Pinched-off nerve endings and their contents of vesicles and cytoplasm together with the attached subsynaptic area of the membrane of the post-synaptic cell. They are largely artificial structures produced by fractionation after selective centrifugation of nervous tissue homogenates.	Synaptosome