Sources and Applications of Tyrosinase in Life Sciences.

Background: Tyrosinase, often recognized as polyphenol oxidase, plays a pivotal role as an enzyme in catalyzing the formation of melanin-a complex process involving the oxidation of monophenols and o-diphenols.

Objective: Tyrosinase functions as a monooxygenase, facilitating the o-hydroxylation of monophenols to generate the corresponding catechols, as well as catalyzing the oxidation of monophenols to form the corresponding o-quinones, exhibiting diphenolase or catecholase activity. This versatile enzymatic capability is not limited to specific organisms but is found across various sources, including bacteria, fungi, plants, and mammals.

Exploration of bioactive molecules from and as an immunity modulator molecular docking and molecular dynamics simulation study.

and are the widely used plant in Ayurvedic systems of medicine. Both plants are well known for their immunomodulatory activity. In the current study, in silico exploration was performed using advanced computational techniques such as molecular docking and molecular dynamics simulation approach.

Characterization of irreversible kinase inhibitors by directly detecting covalent bond formation: a tool for dissecting kinase drug resistance.

Targeting protein kinases in cancer therapy with irreversible small-molecule inhibitors is moving to the forefront of kinase-inhibitor research and is thought to be an effective means of overcoming mutation-associated drug resistance in epidermal growth factor receptor kinase (EGFR). We generated a detection technique that allows direct measurements of covalent bond formation without relying on kinase activity, thereby allowing the straightforward investigation of the influence of steric clashes on covalent inhibitors in different resistant kinase mutants. The obtained results are discussed together with structural biology and biochemical studies of catalytic activity in both wild-type and gatekeeper mutated kinase variants to draw conclusions about the impact of steric hindrance and increased catalytic activity in drug-resistant kinase variants.

Synthesis and biological evaluation of 4-anilinoquinolines as potent inhibitors of epidermal growth factor receptor.

The mutant receptor tyrosine kinase EGFR is a validated and therapeutically amenable target for genotypically selected lung cancer patients. Here we present the synthesis and biological evaluation of a series of 6- and 7-substituted 4-anilinoquinolines as potent type I inhibitors of clinically relevant mutant variants of EGFR. Quinolines 3a and 3e were found to be highly active kinase inhibitors in biochemical assays and were further investigated for their biological effect on EGFR-dependent Ba/F3 cells and non-small cell lung cancer (NSCLC) cell lines.

Chemogenomic profiling provides insights into the limited activity of irreversible EGFR Inhibitors in tumor cells expressing the T790M EGFR resistance mutation.

Reversible epidermal growth factor receptor (EGFR) inhibitors are the first class of small molecules to improve progression-free survival of patients with EGFR-mutated lung cancers. Second-generation EGFR inhibitors introduced to overcome acquired resistance by the T790M resistance mutation of EGFR have thus far shown limited clinical activity in patients with T790M-mutant tumors. In this study, we systematically analyzed the determinants of the activity and selectivity of the second-generation EGFR inhibitors.

High-throughput screening to identify inhibitors which stabilize inactive kinase conformations in p38alpha.

Small molecule kinase inhibitors are an attractive means to modulate kinase activities in medicinal chemistry and chemical biology research. In the physiological setting of a cell, kinase function is orchestrated by a plethora of regulatory processes involving the structural transition of kinases between inactive and enzymatically competent conformations and vice versa. The development of novel kinase inhibitors is mainly fostered by high-throughput screening initiatives where the small molecule perturbation of the phosphorylation reaction is measured to identify inhibitors.

Displacement assay for the detection of stabilizers of inactive kinase conformations.

Targeting protein kinases with small molecules outside the highly conserved ATP pocket to stabilize inactive kinase conformations is becoming a more desirable approach in kinase inhibitor research, since these molecules have advanced pharmacological properties compared to compounds exclusively targeting the ATP pocket. Traditional screening approaches for kinase inhibitors are often based on enzyme activity, but they may miss inhibitors that stabilize inactive kinase conformations by enriching the active state of the kinase. Here we present the development of a kinase binding assay employing a pyrazolourea type III inhibitor and enzyme fragment complementation (EFC) technology that is suitable to screen stabilizers of enzymatically inactive kinases.

Development of a fluorescent-tagged kinase assay system for the detection and characterization of allosteric kinase inhibitors.

Kinase disregulation disrupts the intricate network of intracellular signaling pathways and contributes to the onset of diseases such as cancer. Although several kinase inhibitors are on the market, inhibitor selectivity and drug resistance mutations persist as fundamental challenges in the development of effective long-term treatments. Chemical entities binding to less conserved allosteric sites would be expected to offer new opportunities for scaffold development.

Synthesis of highly functionalized 2(1H)-pyrazinone 3-carboxamide scaffolds.

Synthesis of highly functionalized 2(1H)-pyrazinone 3-carboxamide derivatives is reported. A one-pot, two-step process including the base-mediated reaction of N,N-disubstituted aminoacetonitrile derivatives 18 with 3,5-dihalo-2(1H)-pyrazinones 1 afforded substituted aminoacetonitrile pyrazinone derivative 19, which on subsequent oxidation followed by transamidation of the resulting intermediate with primary or secondary amines gave the corresponding highly functionalized 2(1H)-pyrazinone 3-carboxamide derivatives 21.