Effects of Escherichia coli Alkaline Phosphatase PhoA on the Mineralization of Dissolved Organic Phosphorus

Alkaline phosphatases, which play the key role in the mineralization of organic phosphorus, have been grouped into three distinct families, PhoA, PhoX, and PhoD. PhoA is still an important component of the Pho regulon for many microbes although its distribution is not as wide as that of PhoX and PhoD. However, several questions remain unclear about the effect of PhoA mineralization of dissolved organic phosphorus. In this study, the role of Escherichia coli alkaline phosphatase PhoA (hereinafter referred to as PhoA) in the mineralization of different organic phosphorus including phosphate monoesters, phosphate diesters, and phytic acids was investigated. The influence of the reaction time, organic phosphorus concentration, and L-amino acid on PhoA mineralization was examined. The results show that PhoA specifically hydrolyzes phosphate monoesters except for phytic acid and the optimal reaction time is around 12 h. The PhoA mineralization rate of glucose 6-phosphate disodium (G6P), 5′-adenosine monophosphate (AMP), and sodium glycerophosphate (BGP) significantly decreased by 38.01%, 55.31%, and 57.08%, respectively (p < 0.01), while the concentration of organic phosphorus increased from 0.50 to 5.00 mg/L. Overall, L-amino acids inhibited PhoA mineralization in a concentration-independent manner. The inhibitory effect of neutral amino acids serine (L-Ser) and tyrosine (L-Tyr) was significantly higher than that of basic amino acids arginine (L-Arg), lysine (L-Lys), and histidine (L-His). All the five amino acids can inhibit PhoA mineralization of AMP, with the highest inhibition rate observed for L-Tyr (23.77%), the lowest—for L-Arg (1.54%). Compared with other L-amino acids, L-Tyr has the highest G6P and BGP mineralization inhibition rate, with the average inhibition rates of 12.89% and 11.65%, respectively. This study provides meaningful information to better understand PhoA mineralization.

Metal-Catalyzed Site-Selective Monoacylation of Diols in Aqueous Media

Site-selective reactions of water-soluble biomolecules are being developed to produce efficient conversions in water and water­/solvent mixtures. This review focuses on the use of designs based on bis-bidentate chelation of large metal ions by diols to be acylated by a co-chelated water-stable reagent. Topics discussed include: 1. The preparation and properties of water-stable acyl phosphate monoesters and their reactions with diol-chelated metal ions. 2. Site-selective monoaminoacylation of 3′-terminal diols of RNA and their applications in protein engineering. 3. Site-selective monoacylation of sugars with acyl phosphate monoesters associated with metal ions, including lanthanum and lead. The combination of metal ion, 1,2-diol, and acyl phosphate monoester produces site-selective reactions in aqueous media­ that can produce a general approach to site-selective mono-(amino)acylation in RNA and carbohydrates.1 Introduction2 Synthetic Aminoacylation of tRNA3 Activated Amino Acids in Water4 Metal Ions and Their Effects on the Reactivity of Acyl Phosphate Monoesters5 The Challenge of Site-Selective Acylation of Carbohydrates in Water6 Conclusions and Prospects

Modulation of the nuclearity of molecular Mg(ii)-phosphates: solid-state structural change involving coordinating solvents

The syntheses of mono-, di-, tetra-, hexa-, and polynuclear Mg(ii)-phosphate monoesters are reported.

Increased efficiency in biomimetic Lewis acid–base pair catalyzed monoacylation of diols by acyl phosphate monoesters

Acyl phosphate monoesters are biomimetic acylation reagents that require coordination to metal ions to react with cis-diol substrates in water. With lanthanide catalysts, outcomes are compromised by (1) the competitive lanthanide-promoted hydrolysis of the acyl phosphate reagents as well as by (2) the high affinity of lanthanum ions for the phosphate monoester by-product. Based on analysis of the mechanism of the process, optimizing reaction conditions can selectively inhibit the lanthanum-promoted hydrolysis of acyl phosphate monoesters. Furthermore, using zinc salts and lead salts in place of lanthanides enhances the reactivity of the reactants and causes less complexation of the metal ion with the by-products.