Showing papers by "Elisabetta Meucci published in 1983"
Journal Article•
TL;DR: A striking decrease of bovine kidney alkaline phosphatase activity is observed in vitro when the catalytic assay is performed after preincubation of the enzyme with ascorbic acid (AA), which markedly stabilizes the enzyme even when present in unsaturating amounts.
Abstract: A striking decrease of bovine kidney alkaline phosphatase activity is observed in vitro when the catalytic assay is performed after preincubation of the enzyme with ascorbic acid (AA). The inhibitory effect is a function of AA concentration time and on temperature. Activity decay follows an exponential biphasic course as a function of preincubation time composed by a "fast" phase in the first half hour and by a later "slow" phase of inhibition. Both the rise in preincubation temperature and the increase of the amount of vitamin enhance the degree of inhibition. Ascorbic acid is ineffective as inhibitor when added together with the substrate, p-nitrophenyl phosphate, which in fact markedly stabilizes the enzyme even when present in unsaturating amounts.
6 citations
01 Jan 1983
TL;DR: Ascorbic acid is found strikingly to decrease the activity of bovine kidney alkaline phosphatase in vitro and the presence of the substrate protects the enzyme against the inhibitory action of the vitamin.
Abstract: Ascorbic acid is found strikingly to decrease the activity of bovine kidney alkaline phosphatase in vitro. The inhibition of alkaline phosphatase is a function of ascorbic acid concentration and is time and temperature dependent. The presence of the substrate protects the enzyme against the inhibitory action of the vitamin.
2 citations
Journal Article•
TL;DR: A kinetic approach is described which enables the measurement of the enzyme inactivation rate constant during the reaction course and it is shown that a time-dependent step may be postulated to exist.
Abstract: A kinetic approach is described which enables the measurement of the enzyme inactivation rate constant during the reaction course. A mathematical analysis is presented and it is shown that a time-dependent step may be postulated to exist. Reaction kinetics follow an exponential rule with time as the independent variable and enzymatic activity as the dependent variable. A simple procedure of graphical analysis is reported and the influence on the inactivation rate constant of various conditions (temperature and inhibitor concentration) is evaluated. The method is illustrated by an experimental model: the inactivation of bovine kidney alkaline phosphatase by urea.
1 citations
Journal Article•
TL;DR: Very low amounts of ascorbic acid modify alkaline phosphatase fluorescence, absorption and enzymatic activity, and a strong quenching of enzyme, tryptophan and tyrosine emission together with evident alterations of the protein absorption characteristics are observed.
Abstract: Very low amounts of ascorbic acid modify alkaline phosphatase fluorescence, absorption and enzymatic activity. A strong quenching of enzyme, tryptophan and tyrosine emission together with evident alterations of the protein absorption characteristics are observed. The catalytic activity inhibition probably reflects a perturbation of the active site environment due to the interaction of ascorbic acid with enzyme aminoacyl residues.
1 citations