Differential in vitro inhibition of polyphenoloxidase from a wild edible mushroom Lactarius salmonicolor

J Enzyme Inhib Med Chem. 2009 Apr;24(2):464-70. doi: 10.1080/14756360802190244.

Abstract

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.

MeSH terms

  • Agaricales / enzymology*
  • Benzenesulfonates
  • Catechol Oxidase / antagonists & inhibitors*
  • Catechol Oxidase / isolation & purification
  • Catechol Oxidase / metabolism
  • Catechols / pharmacology
  • Enzyme Inhibitors / pharmacology*
  • Hydrogen-Ion Concentration
  • Kinetics
  • Pyrogallol / pharmacology
  • Salicylates / metabolism
  • Substrate Specificity
  • Temperature
  • Tyrosine / metabolism
  • Tyrosine / pharmacology

Substances

  • Benzenesulfonates
  • Catechols
  • Enzyme Inhibitors
  • Salicylates
  • Pyrogallol
  • 4-methylcatechol
  • Tyrosine
  • Catechol Oxidase
  • sulfosalicylic acid
  • catechol