MODULATION OF THE CATALYTIC ACTIVITY OF PYRIDOXAL KINASE BY METALLOTHIONEIN

  • 1 September 1988
    • journal article
    • research article
    • Vol. 17  (3) , 395-403
Abstract
Pyridoxal kinase displays high catalytic activitiy in the presence of metallothionein. The apoprotein of metallothionein as well as the peptide LYS-CYS-THR-CYS-CYS-ALA exert a strong inhibitory effect upon pyridoxal kinase by suequestering free Zn ions. Several steps intervene in the process of pyridoxal kinase activation, i.e. binding of Zn ions by ATP and interaction of Zn-ATP with the enzyme; but direct interaction between metallothionein and pyridoxal kinase (protein association) could not be detected by emission anisotropy measurements. Since the concentration of free Zn++ in mammalian tissues is lower than 10-9M, it is postulated that the concentration of metallothionein regulates the catalytic activity of pyridoxal kinase. The mechanism of reconstitution of the metalloenzyme yeast aldolase in the presence of metallothionein was also investigated.

This publication has 7 references indexed in Scilit: