Delory & King (1943) published a comparative study of the hydrolysis by faecal alkaline phosphatase of a series of phosphoric esters and established a correlation between the pK values of their second phosphate dissociations, the optimum pH for the enzymic hydrolysis and the Michaelis constants of the esters. They showed that the more acid this phosphate dissociation, the more alkaline was the ...

Alkaline phosphatases (EC 3.1.3.1) purified from human placenta, neutrophils, liver, kidney, and small intestinal mucosa showed a range of Kmvalues for p-nitrophenyl phosphate from 0.017 to 0.038 rriM. The Kmvalues for cysteamine S-phosphate were more variable and ranged from 0.09 to 1.00 HIM. The ratios of the rate of hydrolysis of p-nitrophenyl phosphate to the rate of hydrolysis of cysteamin...

23-Nor-deoxycholic acid is widely used as internal standard in gas-liquid chromatographic studies of bile acids. Two batches of this compound, submitted to conventional alkaline hydrolysis of bile acid conjugates, were found to be transformed into a product with chromatographic properties different from those of "authentic" 23-nor-deoxycholic acid. To identify this "new" product a comparison wa...

The degradation behavior of cefquinome sulphate in alkaline medium at different temperatures was investigated using both first derivative spectrophotometric and HPLC methods. The drug degradation was found to be pH and temperature dependant. The pH-rate profile indicated a first order dependence of Kobs on [OH(-)] at pHs ranging between 9 and 11. Arrhenius plot obtained at pH 10 was linear betw...

The hydrolysis of 0-p-phenylazophenylphosphorothioate by Escherichia coli alkaline phosphatase was studied by the stopped-flow technique. “Burst” kinetics is observed at both acid and basic pH, suggesting that a step following thiophosphorylation is rate-limiting at all pH values. At pH 8.5, activation of a second active site on the enzyme dimer is observed in the transient phase as subsrrate c...

Title STUDIES ON THE MECHANISM OF THE ALKALINE HYDROLYSIS OF THIOLSULFINATES Redacted for Privacy Abstract approved (Major professor) The alkaline hydrolysis of phenylbenzenethiolsulfinate was studied at various pHs in an aqueous solution of 25% dioxane. A pH stat was constructed to follow the rate of disappearance of hydroxide ion under pseudofirst -order conditions. Comparative studies were m...

A sensitive method involving alkaline hydrolysis and HPLC analysis has been developed to detect nanomolar levels of tryptophan dissolved in freshwater. The procedure includes 1) alkaline hydrolysis with nitrogen atmosphere in Teflon-lined Pyrex tubes with 4.2 M sodium hydroxide at 110 degrees C for 16 h, in which ascorbic acid was used as an antioxidant; 2) a determination step, in which trypto...