title: Successful resonance Raman study of cresolase activity of mushroom tyrosinase.
abstract: Mono-oxygenase (cresolase) activity of mushroom tyrosinase (MT) in the presence of 4-[(4-hydroxyphenyl)azo]-benzenesulfonamide (HPABS) was successfully studied by resonance Raman (rR) spectroscopy. HPABS is a synthetic competitive inhibitor (K(i)=7.17 x 10(-6)M) for the cresolase activity with a large extinction coefficient at 365 nm. Upon reacting with MT, HPABS produced an enzyme-inhibitor (EI) complex with sufficiently long life span. Analyzing the ensuing spectrum indicates that the azo tautomer of HPABS binds to the enzyme and retains its geometrical isomeric form in the EI complex. The observed changes in the rR spectrum of HPABS after binding to MT support the idea that an electrophilic attack on the inhibitor has happened. Similar experiments were designed for studying the oxidase activity of MT. However, the enzymatic reaction, even in the presence of 4-[(2,4-dinitrophenyl)azo]-1,2-benzenediols was still fast enough to tan the reaction solution quickly and render its rR spectrum impregnable background.
authors.affiliation: Biochemistry Department, National Research Center for Genetic Engineering and Biotechnology, Tehran, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Shareefi Borojerdi
authors.forename: Kamahldin
authors.initials: K
authors.lastname: Haghbeen
authors.forename: Ali
authors.initials: A
authors.lastname: Asghar Karkhane
authors.forename: Mustafa
authors.initials: M
authors.lastname: Fazli
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Saboury
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D014442:Monophenol Monooxygenase