Inhibitory effect of aluminum on dopamine β-hydroxylase from bovine adrenal gland

Aluminum is a well known neurotoxic agent that is overaccumulated in the substantia nigra of patients affected by Parkinsonʹs disease as well as in certain cerebral areas of other neurodegenerative pathologies such as Alzheimerʹs disease. Although the role of aluminum in neurodegenerative diseases is yet to be clearly understood, the metal ion is known to substantially alter the activity of several key enzymes in the central nervous system. The present paper reports data on the effect of aluminum on the activity of dopamine-β-hydroxylase from bovine adrenal gland utilized as a model study. The metal ion inhibited the activity of this enzyme with a mixed type mechanism following the Michaelis-Menten equation. In the absence of Al, the enzyme exhibited a Km and Vmax of 2.56 mM of 4.12 pmol/min respectively, while in the presence of Al its Km and Vmax were 3.85 mM and 2.86 pmol/min respectively. The potential implications of aluminum in the etiopathogenesis of neurological disorders are discussed.