The trend of modelling native enzymes is increasing day by with the motive mechanistic elucidation enzyme-catalyzed reactions and efficiency catalysts. Most metalloenzymes are capable to activate molecular oxygen due presence metal ions. Among these, copper-based metalloenzyme catechol oxidase has an attractive feature its oxidizing ability generate ortho-quinones from catechol. Moreover, conve...

Male Wistar rats of various age groups were injected daily over a period of 3 weeks with iproniazid (10 micrograms/g body wt.) and L-dihydroxyphenylalanine (L-dopa; 0.1 mg/g body wt.). On the final day 1 h before the termination of the experiment the animals were injected with L-[14C]valine (0.1 microCi/g body wt.). The specific radioactivity of the valine in the proteins of the subcellular fra...

Artificial enzymes with modulated enzyme-mimicking activities of natural systems represent a challenge in catalytic applications. Here, we show the creation artificial Cu metalloenzymes based on generation nanoparticles an enzyme matrix. Different were used, and structural differences between especially influenced controlled size environment that surrounds them. Herein, demonstrated oxidase-lik...

Most of the experimental work concerning the mechanism of melanin production in mammals indicates that the pigment is formed from the amino acid, dihydroxyphenylalanine (dopa), by the action of a specific oxidative enzyme. The evidence for this reaction has in large part been presented by Bloch (l), whose experiments were .confirmed by Laidlaw and others (2). Bloch treated frozen sections of sk...

Melanin pigments are the most common pigments produced in nature and these complex biopolymers are found in species of all biological kingdoms. There are several categories of melanins which include eumelanins, pheomelanins and allomelanins. Eumelanins and pheomelanins are produced from oxidation of tyrosine or phenylalanine to odihydroxyphenylalanine (DOPA) and dopaquinone. Pheomelanin results...

Extensive use of monoamine oxidase inhibitors and imipramine in psychiatric practice has revealed serious toxic reactions. It has been observed that combination of monoamine oxidase inhibitor and imipramine produces a symptom complex characterized by hyperexcitement, motor restlessness and hyperpyrexia (1-6). Furthermore, hypertensive crisis, subarachnoid haemorrhage and pulmonary oedema has be...

tyrosinase is a multifunctional oxidase that is widely distributed in nature. it is a key enzyme in melanin biosynthesis and is involved in determining the color of mammalian skin and hair. in addition it is responsible for the undesirable enzymatic browning that occurs in plant-derived foods, limiting the shelf -life of fresh-cut products with the resultant economic loss.  in recent years ther...

A clonally derived amelanotic melanoma cell line repeatedly has been forced to produce pigment by the inhibitor of DNA synthesis, I-/3-D-arabinofuranosylcytosine (ara-C) at sublethal levels . One ara-C-derived melanotic line has been cloned, and has continued to produce pigment for 2 years on normal medium . The inhibitor is most effective when administered to synchronized cells in four pulses ...

A clonally derived amelanotic melanoma cell line repeatedly has been forced to produce pigment by the inhibitor of DNA synthesis, I-beta-D-arabinofuranosylcytosine (ara-C) at sublethal levels. One ara-C-derived melanotic line has been cloned, and has continued to produce pigment for 2 years on normal medium. The inhibitor is most effective when administered to synchronized cells in four pulses ...