Acid phosphatase deactivation by a series mechanism.
Acid phosphatase (E.C.3.1.3.2.) thermal deactivation at pH 3.77 has been investigated by monitoring the enzyme activity as a function of time in the hydrolysis of p-nitrophenyl phosphate. The experimental curves obtained show a two-slope behavior in a log (activity)versus-time plot, which indicates that deactivation occurs via a complex mechanism. From the dependence of the kinetic parameters on both deactivation and hydrolysis temperatures, it is inferred that the deactivation mechanism involves intermediate, temperature-dependent, less-active forms of the enzyme. This interpretation is confirmed by the results of additional tests in which the temperature was suddenly changed during the deactivation process.
Facolta' di Farmacia, Universita' di Napoli, Naples, Italy.
L
L
Gianfreda
G
G
Marrucci
N
N
Grizzuti
G
G
Greco