title: Truffle thio-flavours reversibly inhibit truffle tyrosinase.
abstract: Tyrosinase is an enzyme having two copper atoms at the reactive site occurring in prokaryotic and eukaryotic organisms. In animals tyrosinase is responsible for pigmentation, in plants for protection of injured tissues or, as in fungi, to harden cell walls. Some of us have previously shown that tyrosinase is involved in truffle development and differentiation. Here we present the purification, the molecular properties and the reversible inhibition of Tuber melanosporum tyrosinase by dimethyl-sulfide and bis[methylthio]methane, the main flavour compounds of black and whitish truffles. The MW(r) is 39000. L-3,4-dihydroxyphenylalanine and L-tyrosine stain corresponding bands as expected for a true tyrosinase. Phenylthiourea, diethyldithiocarbamate and mimosine inhibit L-tyrosine and L-3,4-dihydroxyphenylalanine oxidation.
authors.affiliation: Department of Basic and Applied Biology, Faculty of Sciences, University of L'Aquila, Via Vetoio, I-67010 Coppito, L'Aquila, Italy.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Zarivi
authors.forename: Antonella
authors.initials: A
authors.lastname: Bonfigli
authors.forename: Patrizia
authors.initials: P
authors.lastname: Cesare
authors.forename: Fernanda
authors.initials: F
authors.lastname: Amicarelli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pacioni
authors.forename: Michele
authors.initials: M
authors.lastname: Miranda
mesh_terms: D000364:Agaricus / Q000201:enzymology; D001203:Ascomycota / Q000737:chemistry / Q000201:enzymology*; D002396:Catechols / Q000378:metabolism; D003408:Cresols / Q000378:metabolism; D004050:Ditiocarb / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D005656:Fungal Proteins / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism; D007525:Isoelectric Focusing; D007700:Kinetics; D007980:Levodopa / Q000096:biosynthesis; D008898:Mimosine / Q000494:pharmacology; D008970:Molecular Weight; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism; D010084:Oxidation-Reduction; D010670:Phenylthiourea / Q000494:pharmacology; D013045:Species Specificity; D013379:Substrate Specificity; D013440:Sulfides / Q000302:isolation & purification / Q000494:pharmacology*; D014443:Tyrosine / Q000378:metabolism
chemical_list: D002396:Catechols; D003408:Cresols; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D013440:Sulfides; C474468:bis(methylthio)methane; D014443:Tyrosine; D007980:Levodopa; D008898:Mimosine; D010670:Phenylthiourea; D004050:Ditiocarb; D014442:Monophenol Monooxygenase; C077977:cresol; C004784:dimethyl sulfide