Isotope effects in the tyrosinase catalysed hydroxylation of l-tyrosine methyl derivatives

ABSTRACT

To investigate isotope effects in the hydroxylation of [3′,5′-²H₂]-α-methyl- and [3′,5′-²H₂]-N-methyl-l-tyrosine, they were synthesised using acid catalysed isotope exchange at high temperature. The kinetic and solvent deuterium isotope effects on V_max and V_max/K_m parameters of tyrosinase in its action on methylated derivatives of l-tyrosine were determined using the non-competitive spectrophotometric method. Lineweaver–Burk plots were used to consider the inhibition type of O-methyl-l-tyrosine, revealing that it is an uncompetitive inhibitor of tyrosinase.

KEYWORDS:

• Deuterated l-tyrosine derivatives
• hydrogen-2
• kinetic isotope effects
• reaction mechanisms
• solvent isotope effects
• synthesis by isotope exchange

Disclosure statement

No potential conflict of interest was reported by the authors.