Isotope effects in mechanistic studies of l-tyrosine halogen derivatives hydroxylation catalyzed by tyrosinase

Małgorzata Pająk; Marianna Kańska

doi:10.1007/s10967-017-5526-1

Isotope effects in mechanistic studies of l-tyrosine halogen derivatives hydroxylation catalyzed by tyrosinase

J Radioanal Nucl Chem. 2017;314(3):2123-2128. doi: 10.1007/s10967-017-5526-1. Epub 2017 Oct 23.

Authors

Małgorzata Pająk¹, Marianna Kańska²

Affiliations

¹ Department of Chemistry, Warsaw University, Pasteur 1 Str., 02-093 Warsaw, Poland.
² Department of Biochemistry, 2nd Faculty of Medicine, Medical University of Warsaw, 61 Zwirki i Wigury Av., 02-091 Warsaw, Poland.

Abstract

The kinetic (KIE) and solvent (SIE) isotope effect methods were used to investigate the mechanism of enzymatic hydroxylation of halogenated derivatives of l-tyrosine to l-DOPA catalyzed by the enzyme tyrosinase (EC 1.14.18.1). The values of deuterium KIE and SIE were obtained using the non-competitive method with spectrophotometric measurements. The Lineweaver-Burk plots were used for determination of the inhibition mode of 3'-iodo-l-tyrosine. Based upon kinetic effects values the mechanism of action of enzyme tyrosinase was proposed.

Keywords: Deuterium; Halogenated derivatives of l-tyrosine; Isotope effects; Tyrosinase.