Tyrosinase inactivation in its action on dopa.
Under aerobic or anaerobic conditions, tyrosinase undergoes a process of irreversible inactivation induced by its physiological substrate L-dopa. Under aerobic conditions, this inactivation occurs through a process of suicide inactivation involving the form oxy-tyrosinase. Under anaerobic conditions, both the met- and deoxy-tyrosinase forms undergo irreversible inactivation. Suicide inactivation in aerobic conditions is slower than the irreversible inactivation under anaerobic conditions. The enzyme has less affinity for the isomer D-dopa than for L-dopa but the velocity of inactivation is the same. We propose mechanisms to explain these processes.
Muñoz-Muñoz
J L
JL
GENZ: Grupo de Investigación Enzimología, Departamento de Bioquímica y Biología Molecular-A, Facultad de Biologia, Universidad de Murcia, E-30100, Espinardo, Murcia, Spain.
Acosta-Motos
J R
JR
Garcia-Molina
F
F
Varon
R
R
Garcia-Ruíz
P A
PA
Tudela
J
J
Garcia-Cánovas
F
F
Rodríguez-López
J N
JN
D000363:Agaricales / Q000201:enzymology; D002384:Catalysis; D020134:Catalytic Domain; D004156:Catechol Oxidase / Q000737:chemistry; D004295:Dihydroxyphenylalanine / Q000737:chemistry*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D008956:Models, Chemical; D014442:Monophenol Monooxygenase / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D011485:Protein Binding; D013053:Spectrophotometry / Q000379:methods; D013997:Time Factors
D004295:Dihydroxyphenylalanine; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase; D010100:Oxygen