An alkaline magnesium dependent inorganic pyrophosphatase from the leaf of Amarantus blitum L

The purified inorganic pyrophosphatase from the leaf of Amarantus blitum shows absolute magnesium requirement for its enzyme activity. For maximum enzyme activity, the Mg : PP i ratio was found to be 10:1 at the optimum pH of 9.0. This ratio varies with the shift of the pH. was found to be the true substrate for the enzyme in the presence of the free Mg 2+ ion. Some divalent metal ions and the fluoride anion severely inhibit the enzyme activity in the presence of Mg 2+ . The Michaelis constant (Km) and molecular weight of the enzyme were found to be 4.95· −6 m and 32,860, respectively. This enzyme is strictly specific for inorganic pyrophosphate.