Inhibitory effects of L-3-phenyllacitc acid on the activity of mushnroom pholyphenol oxidase

Abstract

Polyphenol oxidase is the popular enzyme involved in fruit-vegetable browning and melanin synthesis. In the present paper, L-3-phenyllactic acid, a natural bacteriostatic substance, was investigated as an inhibitor of polyphenol oxidase. The results were demonstrated that the residual enzyme activity of polyphenol oxidase decreased gradually with the increase of the concentration of L-3-phenyllactic acid. The L and ΔE values of the reaction system increased gradually. The reversible mixed-type inhibition mode of L-3-phenyllactic acid was determined by Lineweaver Burk plot. At the same time, the results of fluorescence quenching demonstrated that L-3-phenyllactic acid was a quencher of polyphenol oxidase, and the molecular docking study provided the binding mode of L-3-phenyllactic acid and polyphenol oxidase at the molecular level. L-3-phenyllactic acid decreased the activity of polyphenol oxidase and browning of fresh-cut Agaricus Bosporus. This research first studied the inhibitory effect of L-3-phenyllactic acid on the activity of polyphenol oxidase, and would provide a theoretical foundation for the use of L-3phenyllactic acid as anti-polyphenol oxidase agents.

Mechanical properties of stem and physiological–biochemical responses of cucumber under different N and K conditions

“…The changes of PPO activity in stems and leaves are shown in Figure 3. PPO is very common in animals and plants (Ren et al, 2021). As can be seen from Figure 3, the PPO activity under LN, HK, LNLK, and LNHK treatments increased significantly in contrast to the significant decrease under HN, LK, HNLK, and HNHK treatments.…”

“…The restricted movement of sucrose to the sink organs under LK treatment resulted in the rise of sucrose in the leaves and the decline in the stems (Sun et al, 2021) (Figure 3B). PPO has always been the focus of research on the browning of fruits and vegetables (Ren et al, 2021). Kunito, T. et al found that PPO can promote the degradation of lignin in the soil, and the activity of PPO decreases after adding N (Kunito et al, 2009).…”

“…The sugars in tomato (Sung et al, 2015), rice (Khan et al, 2021), stevia (Sun et al, 2021), and corn (Ma et al, 2020), as the main form of photosynthetic products, all had significant changes under stress. Polyphenol oxidase (PPO), which is widely present in animals and plants, was a key enzyme determining the color of mammalian skin, hair, fruits and vegetables, and food softening (Kim et al, 2005;Ren et al, 2021). It was reported by Kunito, T., et al that PPO promoted the degradation of cellulose and lignin in the soil, and its activity decreased with the increase of N (Kunito et al, 2009), which was of importance for the study of stem strength.…”

“…Hence, as the only channel acid reaction described by Pi, z. et al (Pi et al, 2014). The PPO activity was calculated with linear increase in absorbance of the product catalyzed (Ren et al, 2021). Xanthine oxidase was used as one of the most convenient methods to determine the content of SOD because of the specific inhibitory effect of SOD on superoxide radical (Peskin and Winterbourn, 2017;Zhanshen, 2001).…”

Mushrooms Do Produce Flavonoids: Metabolite Profiling and Transcriptome Analysis of Flavonoid Synthesis in the Medicinal Mushroom Sanghuangporus baumii

“…A PAL activity unit is defined as the amount of enzyme required for a 0.01 change in absorbance at 290 nm for 60 min. Polyphenol oxidase (PPO) activity was determined by measuring the oxidation rate of catechol [ 14 ]. A PPO activity unit is defined as the amount of enzyme required for a 0.01 change in absorbance at 525 nm for 1 min.…”