|Titolo: ||Structure-activity relationships of some amino-hydroxy-benzenesulfonic acids and sulfonamides as tyrosinase substrates|
|Data di pubblicazione: ||2011|
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS
|Abstract: ||Background: o-Aminophenols have been long recognised as tyrosinase substrates. However their exact mode
of interaction with the enzyme's active site is unclear. Properly vic-substituted o-aminophenols could help
gain some insight into tyrosinase catalytic mechanism.
Methods: Eight vic-substituted o-aminophenols belonging to two isomeric series were systematically evaluated
as tyrosinase substrates and/or activators and/or inhibitors, by means of spectrophotometric techniques and
HPLC-MS analysis. Some relevant kinetic parameters have also been obtained.
Results: Four o-aminophenolic compounds derived from 3-hydroxyorthanilic acid (2-amino-3-hydroxybenzenesulfonic
acid) and their four counterparts derived from the isomeric 2-hydroxymetanilic acid (3-amino-2-
hydroxybenzenesulfonic acid) were synthesised and tested as putative substrates for mushroom tyrosinase.
While the hydroxyorthanilic derivatives were quite inactive as both substrates and inhibitors, the
hydroxymetanilic compounds on the contrary all acted as substrates for the enzyme, which oxidised them to
the corresponding phenoxazinone derivatives.
General significance: Based on the available structures of the active sites of tyrosinases, the different affinities of
the fourmetanilic derivatives for the enzyme, and their oxidation rates,we propose a new hypothesis regarding
the interaction between o-aminophenols and the active site of tyrosinase that is in agreement with the obtained
|Tipologia:||1.1 Articolo in rivista|