Differential in vitro inhibition of polyphenoloxidase from a wild edible mushroom Lactarius salmonicolor.
The polyphenol oxidase (LsPPO) from a wild edible mushroom Lactarius salmonicolor was purified using a Sepharose 4B-L-tyrosine-p-amino benzoic acid affinity column. At the optimum pH and temperature, the K(M) and V(Max) values of LsPPO towards catechol, 4-methylcatechol and pyrogallol were determined as 0.025 M & 0.748 EU/mL, 1.809 x 10(- 3) M & 0.723 EU/mL and 9.465 x 10(- 3) M & 0.722 EU/mL, respectively. Optimum pH and temperature values of LsPPO for the three substrates above ranged between the pH 4.5-11.0 and 5-50 degrees C. Enzyme activity decreased due to heat denaturation with increasing temperature. Effects of a variety of classical PPO inhibitors were investigated opon the activity of LsPPO using catechol as the substrate. IC(50) values for glutathione, p-aminobenzenesulfonamide, L-cysteine, L-tyrosine, oxalic acid, beta-mercaptoethanol and syringic acid were determined as 9.1 x 10(- 4), 2.3 x 10(- 4) M, 1.5 x 10(- 4) M, 3.8 x 10(- 7) M, 1.2 x 10(- 4) M, 4.9 x 10(- 4) M, and 4 x 10(- 4) M respectively. Thus L-tyrosine was by far the most effective inhibitor. Interestingly, sulfosalicylic acid behaved as an activator of LsPPO in this study.
Dedeoglu
Nurcan
N
Department of Chemistry, Balikesir University Science & Art Faculty, Balikesir, Turkey.
Guler
Ozen Ozensoy
OO
D000363:Agaricales / Q000201:enzymology*; D001557:Benzenesulfonates; D004156:Catechol Oxidase / Q000037:antagonists & inhibitors* / Q000302:isolation & purification / Q000378:metabolism; D002396:Catechols / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011748:Pyrogallol / Q000494:pharmacology; D012459:Salicylates / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D014443:Tyrosine / Q000378:metabolism / Q000494:pharmacology
D001557:Benzenesulfonates; D002396:Catechols; D004791:Enzyme Inhibitors; D012459:Salicylates; D011748:Pyrogallol; C018599:4-methylcatechol; D014443:Tyrosine; D004156:Catechol Oxidase; C003366:sulfosalicylic acid; C034221:catechol