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![Simplified Schematic Representation of L-tyrosine Hydroxylation to L-DOPA by Tyrosinase in the Reaction System with Boron Buffer.
Boron buffer was applied to create complexes with L-DOPA and ascorbic acid (AH2) that minimize suicide inactivation caused by both compounds; AH2 was added to reduce DOPA-quinone back to L-DOPA; hydroxylamine (HA) was added to reduce met-Tyr to deoxy-Tyr in reduced accessibility of L-DOPA and AH2. The scheme was designed according to that described by Marin-Zamora et al. [28]. The black arrows denote the reaction scheme without additives.](publication/308922743/figure/fig7/AS:414649121034246@1475871462950/Simplified-Schematic-Representation-of-L-tyrosine-Hydroxylation-to-L-DOPA-by-Tyrosinase.png)
Simplified Schematic Representation of L-tyrosine Hydroxylation to L-DOPA by Tyrosinase in the Reaction System with Boron Buffer. Boron buffer was applied to create complexes with L-DOPA and ascorbic acid (AH2) that minimize suicide inactivation caused by both compounds; AH2 was added to reduce DOPA-quinone back to L-DOPA; hydroxylamine (HA) was added to reduce met-Tyr to deoxy-Tyr in reduced accessibility of L-DOPA and AH2. The scheme was designed according to that described by Marin-Zamora et al. [28]. The black arrows denote the reaction scheme without additives.
Source publication
Hydroxylation of L-tyrosine to 3,4-dihydroxyphenylalanine (L-DOPA) by immobilized tyrosinase in the presence of ascorbic acid (AH2), which reduces DOPA-quinone to L-DOPA, is characterized by low reaction yields that are mainly caused by the suicide inactivation of tyrosinase by L-DOPA and AH2. The main aim of this work was to compare processes with...
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Citations
... Additionally, ascorbic acid is added to the reaction solution as a tyrosinase inhibitor to deactivate diphenolase activity and as a reducing agent to convert oquinone back to DOPA, thereby promoting the formation of DOPA. 34 To enhance the adhesive properties of UHMW StS-ScS, tyrosine residues were transformed into DOPA residues using tyrosinase from mushroom in the presence of ascorbic acid (0.09 M, Figure 1). The solution before and after the reaction was visually examined and photographed. ...
The presence of a hydration layer in humid and underwater environments challenges adhesive−substrate interactions and prevents effective bonding, which has become a significant obstacle to the development of adhesives in the industrial and biomedical fields. In this study, ultrahigh-molecular-weight (UHMW) silk-elastin-like proteins (SELP) with 3,4-dihydroxyphenylalanine (DOPA) converted from tyrosine residues by tyrosinase exhibited excellent adhesive properties on different interfaces, such as glass, aluminum, wood, polypropylene sheets, and pigskin, under both dry and wet conditions. Additionally, by incorporating trace amounts of cross-linking agents like Fe 3+ , NaIO 4 , and tris(hydroxymethyl) phosphine (THP), the mussel-inspired adhesives maintained a stable and excellent adhesion, broadening the conditions of application. Notably, the UHMW SELP adhesive exhibited remarkable underwater adhesion properties with a shear strength of 0.83 ± 0.17 MPa on glass. It also demonstrated good adhesion to biological tissues including the kidney, liver, heart, and lungs. In vitro cytocompatibility testing using L929 cells showed minimal toxicity, highlighting its potential application in the biomedical field. The sustainable, cytocompatible, cost-effective, and highly efficient adhesive provides valuable insights for the design and development of a new protein-based underwater adhesive for medical application.
... Additionally, ascorbic acid is added to the reaction solution as a tyrosinase inhibitor to deactivate diphenolase activity and as a reducing agent to convert oquinone back to DOPA, thereby promoting the formation of DOPA. 34 To enhance the adhesive properties of UHMW StS-ScS, tyrosine residues were transformed into DOPA residues using tyrosinase from mushroom in the presence of ascorbic acid (0.09 M, Figure 1). The solution before and after the reaction was visually examined and photographed. ...
The presence of a hydration layer in humid and underwater environments challenges adhesive−substrate interactions and prevents effective bonding, which has become a significant obstacle to the development of adhesives in the industrial and biomedical fields. In this study, ultrahigh-molecular-weight (UHMW) silk-elastin-like proteins (SELP) with 3,4-dihydroxyphenylalanine (DOPA) converted from tyrosine residues by tyrosinase exhibited excellent adhesive properties on different interfaces, such as glass, aluminum, wood, polypropylene sheets, and pigskin, under both dry and wet conditions. Additionally, by incorporating trace amounts of cross-linking agents like Fe 3+ , NaIO 4 , and tris(hydroxymethyl) phosphine (THP), the mussel-inspired adhesives maintained a stable and excellent adhesion, broadening the conditions of application. Notably, the UHMW SELP adhesive exhibited remarkable underwater adhesion properties with a shear strength of 0.83 ± 0.17 MPa on glass. It also demonstrated good adhesion to biological tissues including the kidney, liver, heart, and lungs. In vitro cytocompatibility testing using L929 cells showed minimal toxicity, highlighting its potential application in the biomedical field. The sustainable, cytocompatible, cost-effective, and highly efficient adhesive provides valuable insights for the design and development of a new protein-based underwater adhesive for medical application.
... Several approaches have been utilized to enhance stability and catalytic efficiency of enzymes, but immobilizing the enzyme on a nanosupport is a better-opted technique. Recently, nanotechnology advancements have intensified nanocrystals' use as microbial enzyme carriers 11 . Nanoparticles (NPs) have gained significant importance due to their considerable demands in several disciplines, i.e., therapeutic, medicinal delivery, etc. ...
... The enzyme activity unit (IU) was defined as the amount of enzyme required to produce 1 μmol min −1 dopachrome under reaction conditions 11 . ...
The current study focuses on the submerged fermentation of tyrosine hydroxylase (TH) from Aspergillus oryzae IIB-9 and its immobilization on zinc oxide nanocrystals (ZnO-NPs) for increased L-dopa production. The volume of Vogel’s medium (75 ml), period of incubation (72 h), initial pH (5.5), and size of inoculum (1.5 ml) were optimal for maximum TH activity. The watch glass-dried (WG) and filter paper-dried (FP) ZnO-NPs were prepared and characterized using analytical techniques. The UV–Vis spectra revealed 295 and 285 nm absorption peaks for WG-ZnO-NPs and FP-ZnO-NPs dispersed in isopropanol. X-ray diffraction analysis confirmed the crystalline nature of ZnO-NPs. FTIR spectra band from 740 to 648.1/cm and 735.8/cm to 650.1/cm showed the stretching vibrations of WG-ZnO-NPs and FP-ZnO-NPs, respectively. The particle size of ZnO-NPs observed by scanning electron microscopy (SEM) images was between 130 and 170 nm. Furthermore, the stability of immobilized TH on ZnO-NPs was determined by varying the incubation period (10 min for WG-NPs and 15 min for FP-NPs) and temperature (45 °C and 30 °C for WG and FP-NPs, respectively). Incubating enzymes with various copper, iron, manganese, and zinc salts studied the catalytic efficiency of TH. Immobilization of TH on ZnO-NPs resulted in an 11.05-fold increase in TH activity, thus enhancing stability and catalytic efficiency.
... The strong J o u r n a l P r e -p r o o f adhesive forces of mussels in wet and underwater environments were mediated by the secreted mussel foot proteins (Mfps), which are particularly rich in L-3,4-dihydroxyphenylalanine (Dopa), a non-standard of an amino acid derivative [54]. Tyrosinase (EC 1.14.18.1), a coppercontaining oxidase, could catalyze the hydroxylation of tyrosine to L-DOPA residues to confer adhesion characteristics [55]. ...
Skin substitutes are designed to promote wound healing by replacing extracellular matrix. Silk-elastin-like protein is a renewable extracellular matrix-like material that integrated the advantages of silk and elastin-like protein. In this study, electrospun silk-elastin-like protein (SELP) nanofiber membrane covered with bacterial cellulose (BC) was created as a potential skin substitute to mimic gradient structure of epidermis and
dermis of skin. The two layers were glued together using adhesive SELP containing 3,4-dihydroxyphenylalanine (DOPA) converted from tyrosine by tyrosinase. Skin topical drugs commonly used in clinical practice can penetrate through the SELP/BC barrier, and the rate of penetration is proportional to drug concentration. BC with dense fibrous structure can act as a barrier to preserve the inner SELP layer and prevent bacterial invasion, with a blocking permeation efficiency over 99% against four species of bacteria. Cell experiments demonstrated that the reticular fibers of SELP could provide an appropriate growth environment for skin cells proliferation and adhesion, which is considered to promote tissue repair and regeneration. The promising results support this strategy to fabricate a silk-elastin-like protein-based biomaterial for skin substitutes in the clinical treatment of full skin injuries and ulcers.
... It showed that lysozyme was covalently attached to the PA surface by printed tyrosinase through the formation of irreversible complexes. [37]. Three tyrosine residues-Tyr20, Tyr23, and Tyr53-make up the structure of the lysozyme protein and can be catalysed by tyrosinase to produce o-quinones when oxygen is present. ...
... It means that tyrosinase was not bound to PA, but helped to bind lysozyme by forming irreversible complexes. [161] As can be seen from the lysozyme protein structure (Figure 1), it consists of three tyrosine residues (Tyr20, Tyr23 and Tyr53). These residues can be catalysed by tyrosinase in the presence of oxygen to form o-quinones. [162] Further, o-quinones can react non-enzymatically with plasma activated amino groups on PA6,6 to bind lysozyme through Schiff base or Michael addition reaction. ...
This thesis explores the possibilities of printing enzymes using resource-efficient technologies to promote the binding of other proteins and biomaterials on synthetic textiles. This strategy can be used to develop advanced textiles for applications, for example, in antimicrobial, drug delivery and biosensing. Digital inkjet printing was combined with enzyme technology to ensure minimum use of water, chemicals and energy in textile manufacturing processes.
Inks containing two enzymes, lysozyme and tyrosinase, were formulated by adjusting several rheological and ionic properties. The activity of these enzymes was optimised while being printed through two different industrial grade piezoelectric printheads. The theoretical printability of the prepared inks was calculated. The effect of printhead temperature and number of printing passes on the activity was evaluated. Polyester (polyethylene terephthalate) and polyamide-6,6 were pre-treated through several techniques to understand their effect on enzyme adhesion, binding and activity retention. Tyrosinase was used to bind lysozyme on plasma activated polyamide-6,6 surface. The effects of printing these two enzymes in various sequences, i.e. tyrosinase before lysozyme and vice-versa on binding stability and activity, were studied. Influence of the printing process on enzyme kinetics was evaluated. Ability to store and reuse printed fabrics was also studied.
Lysozyme and tyrosinase containing inks showed activity retention of 85% and 60%, respectively. Activity of lysozyme containing ink was optimum at 10–15 mPa.s when glycerol was used as a viscosity modifier. However, the optimum viscosity for tyrosinase containing ink was at 6–9 mPa.s, and carboxymethyl cellulose was found to be the most favourable modifier. For both inks, a surfactant amount below the critical micelle concentration was considered to be the most effective for printing. Among the studied fabric pre-treatment methods (alkaline, cutinase and plasma), it was found that the activity and stability of the enzyme were dependent on the nature of the pretreatment processes, which can be beneficial for different application areas, e.g. drug release and bio-sensing. Upon printing both inks on a plasma treated polyamide-6,6, tyrosinase was able to catalyse lysozyme protein to bind it on fabric. A maximum of 68% lytic activity was retained by lysozyme when it was printed after tyrosinase. This fabric showed inhibition of bacterial growth and retained almost half of its initial activity when cold stored for a month.
... It indicated that printed tyrosinase covalently bound lysozyme on PA surface by forming irreversible complexes. [34] Lysozyme protein structure consists of three tyrosine residues (Tyr20, Tyr23, and Tyr53) which can be catalyzed by tyrosinase in the presence of oxygen to form o-quinones. [35] These o-quinones might have further non-enzymatically reacted with plasma activated amino groups on PA surface to crosslink lysozyme through Maillard or Michaelis addition reaction. [1,2] Each printed sample was subjected to check lysozyme activity against MLC. ...
An ink containing tyrosinase catalyzes the tyrosine residues on lysozyme protein to bind it on a plasma‐treated polyamide‐6,6 (PA) fabric. Inkjet printing enables controlled and sequential deposition of two enzymes on PA which is necessary for proper binding. The effect of different printing sequences on crosslinking stability and enzymatic activity is presented. The lysozyme bound on the fabric shows satisfactory antimicrobial activity. The printed fabric retains about 68% of the ink activity when tyrosinase is printed before lysozyme. Further, this fabric retains about 24% of the initial activity up to four reuses. The fabric shows acceptable inhibition of bacterial growth and retains almost half of its initial activity when cold stored for a month. This work shows the potential of protein binding on textile surface using various means of sustainable technologies, namely enzyme, inkjet, and plasma. An antimicrobial enzyme (lysozyme) is bound on polyamide (nylon) fabric surface by digital printing. This study uses several sustainable technologies as an alternative to conventional chemical and energy‐intensive processes. Using the strategy of this study, other biomaterials can be bound on various textile surfaces for advanced applications.
... The best measure of the global oxidative state of a proteome is the level of methionine oxidation, which occurs via the addition of a single oxygen atom, creating methionine sulfoxide with a mass shift of +15.99 Da, homologous to that of hydroxylation [31,32]. However, protein extraction and preparation can increase the likelihood of forming oxidised methionine and even electrospray ionisation can result in this modification [29,33,34]. Due to the multiple possible end-points of hydroxyl attack, the identification of oxidised phenylalanine may help in determining if PB-DOPA has been formed from incorporation or from hydroxyl attack. ...
... Due to the multiple possible end-points of hydroxyl attack, the identification of oxidised phenylalanine may help in determining if PB-DOPA has been formed from incorporation or from hydroxyl attack. Within plant and animal tissues, the conversion of tyrosine to L-DOPA can be carried out by the enzyme tyrosinase, which has also been used in industrial synthesis of L-DOPA and is essential to the production of dopamine in the human brain [33,34]. Unlike oxidation reactions, the enzyme tyrosinase has the capacity to generate peptide-bonded DOPA (from PB-tyrosine conversion) without generating other oxidised amino acid residues such as ortho-and meta-tyrosine. ...
... To overcome the poor detection of low-ion-abundance peptides from PB-DOPA proteoforms, a method for creating a positive control spectral library needs to be produced to enable future application to clinical samples by enabling DIA analyses. A method for generating a positive control spectral library and avoiding the high cost of chemically synthesising a DOPA-containing peptide library is to use the enzyme tyrosinase to specifically modify tyrosine residues to L-DOPA [34,35]. The aim of this work is to establish the use of tyrosinase to convert proteomes, enabling subsequent analyses. ...
Proteinopathies are protein misfolding diseases that have an underlying factor that affects the conformation of proteoforms. A factor hypothesised to play a role in these diseases is the incorporation of non-protein amino acids into proteins, with a key example being the therapeutic drug levodopa. The presence of levodopa as a protein constituent has been explored in several studies, but it has not been examined in a global proteomic manner. This paper provides a proof-of-concept method for enzymatically creating levodopa-containing proteins using the enzyme tyrosinase and provides spectral evidence of in vitro incorporation in addition to the induction of the unfolded protein response due to levodopa.
... Catecholaminergic neurotransmitters-such as dopamine, norepinephrine, and adrenaline-are synthesized through the hydroxylation of tyrosine to L-dihydroxy-phenylalanine by tyrosine hydroxylase (43). Catecholaminergic levels show downward trends in depressed patients. ...
Objectives:
Gleditsiae spina (GS) is a natural antidepressant but its mechanisms of action remain unclear. In the present study, taxifolin (Tax) was selected to determine the role of flavonoids in the antidepressant effects of GS.
Materials and methods:
Urine samples from C57BL/6 mice were analyzed based on ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q/TOF-MS). Then, we investigated the therapeutic effects of GS and Tax in depression models in vivo. An integrated metabolomic approach was used to examine the metabolic profiles of GS/Tax groups and corticosterone model groups (Cor). Metabolic networks in response to GS/Tax treatment were established for the comparison of antidepressant activities.
Results:
Corticosterone exposure significantly increased serum levels of corticosterone but decreased serum levels of 5-hydroxytryptamine and sucrose consumption (P<0.01). Treatment with GS and Tax improved all measured variables compared to those of the corticosterone-exposed group (P< 0.01). The antidepressant effects of GS and Tax involved the regulation of pentose and glucuronate interconversions, arginine and proline metabolism, phenylalanine metabolism, taurine and hypotaurine metabolism, and the citrate cycle.
Conclusion:
These findings indicate that flavonoids form the pharmacodynamic basis of the antidepressant effects of GS. Moreover, our findings highlight that integrated metabolomics provides a powerful tool to study the mechanisms and material basis of Chinese herbs.
... Deactivated tyrosine is formed from oxy-tyrosine during the suicide inactivation. Concisely, this inactivation takes place when the diphenolic substrates are processed as monophenols, and one of the Cu ions is reduced in this route [10] . However, this enzyme can be reactivated by electron donor molecules, e.g. ...
Tyrosinase and tyrosinase-related proteins (TYRPs) play an important role in melanogenesis. TYRPs present in the membrane of melanosome, are known to function in the activation and stabilization of tyrosinase, melanosome synthesis, increase eumelanin/pheomelanin ratio, and in reducing oxidative stress due to its peroxidase effect. Besides, the tyrosinase enzyme is the main enzyme that catalyzes the rate of melanin synthesis, whereas the downregulation of tyrosinase is the most prominent way of developing the inhibitors of melanogenesis. The active site of the tyrosinase-like subdomain of TYRP-1 contains two zinc ions, while that of tyrosinase contains two copper ions. This article focuses on the role of an isoform of TYRP, namely TYRP-1, in melanogenesis, the character of its active site, and the mechanism of action of plant-based lightening agents. © 2021. Journal of Advanced Pharmacy Education & Research | Published by SPER Publication.
