A catecholase fromLaccaria laccataa wild edible mushroom and its catalytic efficiency in organic media

Abstract

In this study, catecholase was purified from Laccaria laccata by affinity chromatography and the enzyme activity was investigated in organic media. Among the tested substrates, the highest catecholase activity was observed in 4‐MC, DHPPA, and L‐DOPA. A single band around 58.1 kDa was observed on SDS‐PAGE of the purified enzyme. Km values were calculated as 0.25, 0.40, and 0.83 mM for 4‐MC, DHPPA, and L‐DOPA, respectively. The highest Vmax value was calculated as 2500 U/mg protein for 4‐MC. The inhibitors used in this study showed mixed type inhibition kinetics for all tested substrates. Ascorbic acid was found to be most effective inhibitor with low Ki value. Also, it was observed that LacPPO is more stable at optimum pH and temperature. In addition, LacPPO was found to be an effective biocatalyst in organic medium. According to the results obtained, the purified enzyme may be useful for some industrial and/or clinical purposes. Practical applications A small number of wild mushrooms can be used as food, and some of them are traditionally used in the treatment of certain diseases. L. laccata (wild edible mushroom) is first time reported as a PPO source. The results obtained in this study may be useful for understanding the behavior of mushroom catecholases. In addition, LacPPO may be used in the production of compounds which can be synthesized in the presence of organic solvents such as food additives and pharmaceutical drugs in need of natural compounds since the enzyme has the ability to catalyze the reaction in the environment of the organic solvent.

Purification and biochemical characterization of polyphenol oxidase extracted from Kirmizi Kismis grape (Vitis viniferaL.)

“…The effects of metal ions on PPO obtained from Laccaria laccata , an edible wild mushroom, were investigated using 4‐MC, L‐DOPA, and DHPPA as substrates. For 4‐MC, the strongest inhibitory effect was seen on Hg 2+ , and a slightly increase in activity was reported for Al 3+ and Na + (Kolcuoğlu et al., 2018). It is possible that metal ions behave in a different way toward proteins as ligands.…”

“…Sulfite compounds is attributed to the formation of stable colorless products with o‐quinones or the binding active center of polyphenol oxidase. However, their use has been restricted due to the adverse effect on human health (Hussein et al, 2015; Kolcuoğlu et al., 2018; Rapeanu et.al., 2006 ). Citric acid inhibits the enzyme due to its specificity against histidine residues in the active site of the polyphenol oxidase, lowering the pH value, thus, facilitating the chelation of copper in the active site, and the conformation of the enzyme was gradually unfolded with increasing pH (Liu et al., 2013; Yoruk & Marchall, 2003).…”

“…In similar studies, the Ki value of PPO isolated from Chinese parsley (Coriandrum sativum) was found to be 0.93 and 1.89 mM in the presence of 4‐MC and catechol substrates respectively by using citric acid inhibitor and the inhibition type for both substrates was competitive (Lin et al, 2016). K i value for Laccaria Laccata PPO using 4‐MC substrate, were found to be 2.084 and 0.0151 mM for sodium metabisulfite and ascorbic acid, respectively (Kolcuoğlu et al, 2018). K i values for borage PPO were found as 0.18 mM was for ascorbic acid and 0.20 mM for sodium metabisulfite using 4‐MC substrate.…”

“…For 4-MC, the strongest inhibitory effect was seen on Hg 2+ , and a slightly increase in activity was reported for Al 3+ and Na + (Kolcuoğlu et al, 2018). It is possible that metal ions behave in a different way toward proteins as ligands.…”

Synthesis of flurbiprofen thiadiazole urea derivatives and assessment of biological activities and molecular docking studies

“…Tyrosinase activity was measured spectrophotometrically at 492 nm using L‐DOPA as substrate (Karakaya et al, 2019). Tyrosinase activity was measured in units (U) and was defined as the amount of product generated in 1 mL of the reaction mixture in 1 min (Kolcuoglu et al, 2018). The molecules to be used as inhibitors in the study were dissolved in DMF and solutions of different concentrations were prepared.…”