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Fungal Enzymes in Organic Pollutants Bioremediation
Published in Pankaj Bhatt, Industrial Applications of Microbial Enzymes, 2023
Adam Grzywaczyk, Wojciech Smułek, Jakub Zdarta, Ewa Kaczorek
Tyrosinase (EC 1.14.18.1) is a metalloenzyme (contains copper) glycoprotein found in fungal, animal, bacterial, and plant cells. Tyrosinase’s ability to react with phenols makes it participate in the process of melanogenesis; as a result of which, melanin is produced. This ability has been exploited for the degradation of compounds such as cyanide, phenol, chlorophenols, cresols, and dyes (Ba & Vinoth Kumar, 2017; Nawaz et al., 2017; Osuoha et al., 2019). Martínkova et al. report almost complete degradation of free cyanide (8.3–520 mg/L) in the model and actual coking the wastewater obtained by using recombinant cyanide hydratase in the first step, and tyrosinase degradation as the second step of the process. Phenol (1,552 mg/L) was completely removed from the actual coke wastewater in 20 hours, and the cresols (540 mg/L) were removed by 66% under the same conditions (Martínková & Chmátal, 2016).
iMRI for Clinical Gene Therapy
Published in Yashwant V. Pathak, Gene Delivery Systems, 2022
Disha Patel, Khushboo Faldu, Jigna Shah
Initially, MRI gene expression tracking was based on imaging of MR substrate-attractable receptors/enzymes, which were expressed when transgenes transduced the target. MR signals were generated due to the increased concentration of paramagnetic substrates at the target sites, as MR substrate-attractable receptors/enzymes had an increased affinity for binding or metabolizing the paramagnetic substrates (42). Tf-bound super-magnetic contrast dyes can be used for tumor cell imaging due to increased expression of human transferrin receptor (TfR) genes in these cells (14). Tyrosinase is an enzyme involved in melanogenesis. It has a higher affinity for binding to metal ions like ferric ions that leads to signal hyperintensity on T1-weighted images (43). This capability of tyrosinase is used for catalyzing the conversion of contrast agents to higher relaxivity in tyrosinase-induced MRI (41).
Sida cordata assisted bio-inspired silver nanoparticles and its antimicrobial, free-radical scavenging, tyrosinase inhibition, and photocatalytic activity (4 in 1 system)
Published in Particulate Science and Technology, 2023
Brindhamani Ravi, Ganesh Mani, Hemalatha Pushparaj, Hyun Tae Jang, Vijayabaskaran Manickam
The mushroom tyrosinase inhibition activity of SC-AgNPs was summarized in Figure 12. The green synthesized SC-AgNPs exhibited potent inhibition (from 13.46 ± 2.45 to 98.25 ± 1.25% (110 µg/ml) of mushroom tyrosinase enzyme. The inhibition was comparable to the standard Kojic acid used at 60 µg/ml (99.82 ± 2.568%). No activity was observed in negative solvent control. Moreover, the Ic50% value (amt of SC-AgNPs require to inhibit 50% of mushroom tyrosinase) was found as 47.8 µg/ml. Tyrosinase is a copper-containing metaloenzyme, in which copper is present in its active site and catalyzes to change the oxidative state of copper atoms (Lee and Kim 1995). The tyrosinase enzyme is involved in melanin formation by catalyzing the conversion of tyrosine to di-hydroxy phenylalanine (DOPA) and from DOPA to DOPA quinones through the oxidation process. The DOPA quinone is a highly reactive compound, which polymerizes to yield melanin pigments that cause a serious esthetic problem for human beings. The excessive melanin formation can be controlled by the inhibition of tyrosinase enzyme and transport of melanosomes to the stratum corneum of the skin by natural and synthetic antioxidant supplementation (Pawelek and Körner 1982). Therefore, many tyrosinase inhibitors and antioxidant agents have been tested as a way of preventing the overproduction of melanin in epidermal layers (Armstrong et al. 2013; Govindappa et al. 2016).
Antioxidant and anti-tyrosinase activities of quercetin-loaded olive oil nanoemulsion as potential formulation for skin hyperpigmentation
Published in Journal of Dispersion Science and Technology, 2022
Cristiane C. Silva, Rogério B. Benati, Taís N. C. Massaro, Karina C. Pereira, Lorena R. Gaspar, Priscyla D. Marcato
In our study, kojic acid, a known tyrosine inhibitor, allowed the inhibition of 79.61 ± 5.86% of tyrosinase and also reached a plateau at a concentration of 7.1 μg/mL. QT-NE was able to inhibit 56.24 ± 3.38% of tyrosinase while QT free inhibited 20.37 ± 5.94% of the enzyme, comparing the two samples at the concentration of 5 μg/mL as shown in the Figure 6. Tyrosinase inhibition by quercetin, according to the literature,[24,78] happens by the bind of quercetin hydroxyls with the active tyrosinase site, chelating with copper from the enzyme. In this way, the incorporation of QT in nanoemulsion increases the tyrosinase inhibition compared to free QT, which hinders the formation of melanin and it can contribute to the lightening of dark spots of hypermelanosis, which includes the inhibition of the melasma signaling cascade.