1. An inositol monophosphatase was purified to homogeneity from bovine brain. 2. The enzyme is a dimer of subunit Mr 29,000. 3. The enzyme hydrolyses both enantiomers of myo-inositol 1-phosphate and both enantiomers of myo-inositol 4-phosphate, but has no activity towards inositol bisphosphates, inositol trisphosphates or inositol 1,3,4,5-tetrakisphosphate. 4. Several non-inositol-containing mo...

A hexitol-inducible, phosphoenolpyruvate-dependent phosphotransferase system was demonstrated in Streptococcus mutans. Cell-free extracts obtained from mannitol-grown cells from a representative strain of each of the five S. mutans serotypes (AHT, BHT, C-67-1, 6715, and LM7) were capable of converting mannitol to mannitol-1-phosphate by a reaction which required phosphoenolpyruvate and Mg2+. Ma...

Neisseria gonorrhoeae readily underwent autolysis when suspended in N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffer at alkaline pH values. Autolysis was inhibited by the addition of Mg2+ or other divalent cations. Autolysis was also suppressed at acid pH (pH 6.0). Suspension of cells in buffer was accompanied by the hydrolysis of peptidoglycan. The rate of peptidoglycan hydro...

The effects of mono- and divalent ions on Ca2+-gated cardiac muscle Ca2+-release channel (ryanodine receptor) activity were examined in [3H]ryanodine-binding measurements. Ca2+ bound with the highest apparent affinity to Ca2+activation sites in choline chloride medium, followed by KCl, CsCl, NaCl, and LiCl media. The apparent Ca2+ binding affinities of Ca2+ inactivation sites were lower in chol...

Plasma membrane Mg2+, Ca2+ ATPases were isolated from Dunaliella parva by differential centrifugation and subsequent sucrose gradient centrifugation and analyzed for their properties with special emphasis on ecophysiological requirements of this extremely salt-tolerant alga. Most properties (Vmaxand AfM-values, substrate specificity, vanadate and DES sensitivity, resistance against ouabain) ind...

BACKGROUND Metal ions participate in the three-dimensional folding of RNA and provide active centers in catalytic RNA molecules. The positions of metal ions are known for a few RNA structures determined by X-ray crystallography. In addition to the crystallographically identified sites, solution studies point to many more metal ion binding sites around structured RNAs. Metal ions are also presen...

Unlike human erythrocytes, those from avian species, such as turkeys and chicks, rapidly incorporate myo-[3H]inositol into membrane phospholipids. The mechanisms regulating [3H]Ins labelling of phosphatidylinositol have been investigated using turkey erythrocyte membranes. In the absence of added nucleotides, [3H]inositol incorporation appears to proceed via phosphatidylinositol/inositol exchan...

The mechanism of the fluorescence quenching of aqueous thionine by various metal ions (Ce3+_, Fe2+, Mn2+, Mg2+, Cs+ and Na+) was studied at pn = 2.5. The following Stern-Volmer constants (K s v) were determined: XSv(Fe2+) == 1.13 dm3 mol -1 , Ksw(Mn2+) = 0.24 dm3 mol"1, Ksv(Ce3+) = 0.24 dm3 mol -1, i£sv(Cs~) — 0.03 dm3 mol -1 . At concentrations below 1 mol.dm -3 Na2S04 and MgS04 are very weak ...

The biosynthesis of bacteriophage T4 tRNAPro, tRNASer, and tRNAIle requires enzymatic removal of extra nucleotides from the 3' terminus of the respective precursor RNAs. A ribonuclease activity capable of catalyzing such reactions has been partially purified from uninfected Escherichia coli using an artificial precursor RNA as substrate. A number of ribonuclease activities were resolved during ...

Sodium, calcium and magnesium ions are essential for the biological activity of many polyelectrolytes. This activity depends on a condensation of the metal ions. There are several clues, which suggest that interactions between the polyelectrolyte and metal ions depend on a hydration of the ion. This accounts for the great interest in the hydration of metal ions, particularly in the systems cont...