The Na(+)/K(+)-ATPase mediates electrogenic transport by exporting three Na(+) ions in exchange for two K(+) ions across the cell membrane per adenosine triphosphate molecule. The location of two Rb(+) ions in the crystal structures of the Na(+)/K(+)-ATPase has defined two "common" cation binding sites, I and II, which accommodate Na(+) or K(+) ions during transport. The configuration of site I...

The pyridoxal 5'-phosphate-dependent enzyme dialkylglycine decarboxylase (DGD) is activated by K+ and Rb+ ions, whereas Li+ and Na+ ions are inhibitory. A binding site for alkali metal ions close to the active site (site 1) was discovered in the crystal structure of DGD, and an exchange of K+ for Na+ at this site was shown to affect the conformation of two active site residues [Toney, M. D., Ho...

Concentrations of inorganic ions (Cl , H + , SO4 2, NO3 , NH4 + , Na + , K + , Ca 2+ , Mg 2+ ) and metals (V, Ni, Cu, Pb, Cr Mn, Al, Fe) in bulk precipitation and PM10 samples collected in the metropolitan area of Costa Rica were analyzed. Good correlations between acidity in bulk precipitation with the concentrations of aerosols in the air were observed. The scavenging of the pollutants from t...

The major protein fraction, alpha-globulin, of sesame seed (Sesamum indicum L.) contains subunits which are associated predominantly by hydrophobic interactions. Effects of various salts show the following effectiveness of anions in dissociating the proteins, SO4(2-) less than Cl- less than Br- less than ClO4- less than SCN- less than or equal to I- less than CCl3COO-, the first two members bei...

The major protein fraction, a-globulin, of sesame seed CS’esamum indicum L.) contains subunits which are associated predominantly by hydrophobic interactions. Effects of various salts show the following effectiveness of anions in dissociating the proteins, SO,*< Cl< Br< C104< SCN4 I< CCl,COO-, the first two members being association-inducing ions. CC1,COONa is found to be the most effective amo...

X-Ray diffraction studies have been made of the crystalline luminescent material Na+-E$+ p”-alumina for three different erbium ion concentrations; equivalent to 100, 72 and 26% substitution of Na’ ions (Na, +,,-&ErXMgfilll 7, for x = 0.56, 0.40 and 0.1 4, respectively, and y = 2/3). The results form thereafter a structural basis for molecular dynamics (MD) simulations, which, in turn, are used ...

Elevated major ions (or salinity) are recognised as being a key contributor to the toxicity of many mine waste waters but the complex interactions between the major ions and large inter-species variability in response to salinity, make it difficult to relate toxicity to causal factors. This study aimed to determine if the toxicity of a typical saline seepage water was solely due to its major io...

The addition of small amounts of multivalent cations to solutions containing double-stranded DNA leads to inter-DNA attraction and eventual condensation. Surprisingly, the condensation is suppressed in double-stranded RNA, which carries the same negative charge as DNA, but assumes a different double helical form. Here, we combine experiment and atomistic simulations to propose a mechanism that ...

background: the present study investigated the effect of the middle east dust storm episodes on the concentration and composition of pm 10 during april to september 2013 in sanandaj city, western iran. methods: sampling was once every six days, and on dusty days using an omni air sampler. the pm 10 sample was collected on polytetrafluoroethylene filters. average of 24 h values of pm 10 mass con...

zeolites due to their structures can be used as molecular sieves for purification of materials and solutions. zeolites with phi and sod structure are so common and applicable for this purpose. hydroxy sodalite and phillipsite are the more abundant members of zeolites which display good selectivity for very small molecules and some ions such as sr, pb, zn, cu and rb. there is not any pure natura...