The development of new
catechol-O-methyltransferase inhibitors has led to an improvement in the treatment of
Parkinson's disease. However, despite the fact that the soluble
isoform has been extensively investigated, few studies have been published concerning membrane
isoform chromatographic recovery and bioactivity levels. In this work, chromatographic profiles of both
catechol-O-methyltransferase isoforms were compared using quaternary
amine as a
ligand to evaluate its activity levels and recovery rates. Results show that both
proteins required different conditions for adsorption; the soluble
isoform adsorption was performed at low ionic strength, while the membrane
isoform required increasing linear
salt gradient. However, the application of 0.5%
Triton X-100 promoted membrane
isoform adsorption even at low ionic strength. Indeed, chromatographic conditions of both
isoforms became similar when
detergents were applied. The developed methods also appear to be highly effective in bioactivity recovery, presenting rates of 107% for soluble
protein and 67 and 91% for membrane
isoform without and with
detergents, respectively. The chromatographic strategies with and without
detergents resulted in a 4.3- and sevenfold purification, respectively, corresponding to specific activity values of 331 and 496 nmol/h/mg. Thus, the use of Q-
sepharose as
anion exchanger was effective in the recovery of both
enzymes, which is a requirement for further kinetic and pharmacological trials.