Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.10.3.1 (tyrosinase)
 9,065 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At neutral (7.0) and slightly basic (8.2) pH, L-3,4-dihydroxyphenylalanine (L-DOPA), 3,4,5-trihydroxyphenylalanine (5-OH-DOPA) and 3,4-dihydroxyphenylethylamine (dopamine) undergo autoxidation. The binding of radiolabeled oxidation products of L-DOPA, 5-OH-DOPA and dopamine to membrane proteins was compared by a filtration procedure. Membranes from tentacles of the sea anemone Metridium senile bind significantly more 5-OH-DOPA than L-DOPA and dopamine. Membranes from rat brain and brains from the three-spined stickleback Gasterosteus aculeatus, bind significantly more dopamine than L-DOPA and 5-OH-DOPA. Membranes from Metridium contain an o-diphenol O2: oxidoreductase (tyrosinase). In the absence of inhibitors, enzymatic oxidation causes a fiftyfold increase in binding of L-DOPA and a more than tenfold increase in binding of dopamine, whereas the binding of 5-OH-DOPA only is increased by 10%. It is concluded than 5-OH-DOPA more easily undergo autoxidation than L-DOPA and dopamine, but its quinone form is probably less reactive with membrane proteins. The suitability of tyrosinase-mediated biosynthesis of L-DOPA and 5-OH-DOPA versus tyrosine hydroxylase-mediated biosynthesis of L-DOPA and dopamine in primitive nervous systems and in the vertebrate CNS is discussed on the basis of the cytotoxic potential through irreversible binding to membrane proteins of oxidation products of the catechol compounds formed.
J Neural Transm Gen Sect 1990
PMID:3,4-Dihydroxyphenylethylamine, L-3,4-dihydroxyphenylalanine and 3,4,5-trihydroxyphenylalanine: oxidation and binding to membranes. A comparative study of a neurotransmitter, a precursor and a neurotransmitter candidate in primitive nervous systems. 197 46

DNA from the Streptomyces plasmid pIJ702 was mutagenized in vitro using hydroxylamine and transformed into Streptomyces lividans. One plasmid with temperature-sensitive replication (pMT660) and one plasmid with a temperature-sensitive tyrosinase (pMT661) were isolated. The plasmid pMT661 contains a novel PstI restriction endonuclease site within the tyrosinase gene.
J Gen Microbiol 1985 Jun
PMID:Temperature-sensitive mutants of the Streptomyces plasmid pIJ702. 299 43

The gene from Streptomyces glaucescens coding for an inducible tyrosinase was cloned using the low copy vector pIJ41 and the melanin-negative strain Streptomyces lividans TK23 as host. Hybridisation experiments as well as complementation studies showed that melC mutant strains carry large deletions of more than 10.5 kb, comprising the structural gene for tyrosinase, while melA and melB strains carry mutations in genes involved in the expression of tyrosinase activity. Strong DNA homology was found between the Streptomyces antibioticus and the S. glaucescens tyrosinase structural genes and both genes showed a similar regulation when introduced into melanin-negative hosts. While both tyrosinases exhibited clear induction in S. glaucescens, constitutive expression was observed in S. lividans. Northern blot experiments showed that tyrosinase expression is regulated at the transcriptional level and that the gene (822 bp) is part of a 2.3 kb transcript. The main start of the mRNA at about 475 bp upstream from the tyrosinase N-terminus was located by S1-mapping experiments.
Mol Gen Genet 1985
PMID:Cloning and expression of the genetically unstable tyrosinase structural gene from Streptomyces glaucescens. 299 65

The 10.8 kb plasmid pJV1, isolated from Streptomyces phaeochromogenes, has a high copy number (about 150) and a broad host range among Streptomyces spp. Several pJV1 derivatives carrying the thiostrepton resistance gene (tsr) of S. azureus were made. One derivative, pWOR191, was shown to promote its own transfer and to mobilize chromosomal markers in S. lividans. Another derivative, pWOR109, was non-transmissible. Deletion in vitro of a segment of pWOR109 gave pWOR120 (5.6 kb), which has single BamHI and Bg/II sites shown to be capable of accepting 'foreign' DNA such as a previously cloned S. antibioticus DNA fragment encoding tyrosinase, giving vectors (pWOR125, pWOR126) with properties resembling the well-established multicopy vector pIJ702. Shuttle vectors capable of functioning in both S. lividans and Escherichia coli were also constructed. The region of pJV1 essential for replication and maintenance was localized to a 2.5 kb segment. Stable maintenance of pWOR109 and pWOR120 was observed in the presence of derivatives of pIJ101, the progenitor of pIJ702.
J Gen Microbiol 1986 Aug
PMID:Properties of in vitro recombinant derivatives of pJV1, a multi-copy plasmid from Streptomyces phaeochromogenes. 302 35

The results of studies on genetic control of resistance to antibiotics in Streptomyces strains are discussed. Cloning and sequence analysis of resistance genes yield information concerning their expression in homo- and heterologous systems, allow analysis of signal sequences responsible for initiation of transcription and translation. Cloning of genes coding for resistance to neomycin,viomycin, thiostrepton in Streptomyces and Bac. licheniformis ermD gene made them convenient selective markers for constructing vector molecules, useful for identification of homology regions in S. fradiae aph gene and TnS of E. coli; the site homologous to ermD gene has been thus revealed in S. erythreus chromosome. Possibilities of the studies aimed at elucidation of instability of many actinomycete characters using determinants of natural multiple resistance to antibiotics as a model are demonstrated. It has been shown that genetic instability is not related to the loss of plasmids and is associated with genes having chromosomal location. Simultaneous high frequency loss of a number of resistance characters determined by non-linked genes suggests the participation in gene activity regulation of actinomycete genome rearrangements. This is confirmed by evidence for such rearrangements found in strains with mutant phenotypes, including deletions in tyrosinase and streptomycin phosphotransferase genes in Mel- and StrS strains of S. reticuli and S. glaucescens.
Mol Gen Mikrobiol Virusol 1985 Mar
PMID:[Genetic control of Actinomycetes resistance to antibiotics]. 391 22

A comprehensive survey of the interaction of the copper proteins and oxygen is presented including a correlation of structure, function, and other properties of the known copper oxidases and of hemocyanin. The origin of their blue color and the structure of copper complexes and copper proteins are related to the oxidation state of copper ion and relevant electronic transitions probably arising from the formation of charge transfer complexes. The oxygen reactions of hemocyanin, ceruloplasmin, and cytochrome oxidase show half-saturation values far below the other Cu enzymes. The formation of hydrogen peroxide as a reaction product is associated with the presence of one Cu atom per oxidase molecule or catalytic system. Water is the corresponding product of the other Cu oxidases with four or more Cu atoms per molecule, except for monoamine oxidase. Mechanisms for the oxidase action of the two and four electron transfer Cu oxidases and tyrosinase are proposed. These reactions account for the number, the oxidation-reduction potential, and the oxidation state of Cu in the resting enzyme, the cyclical change from Cu(II) to Cu(I), the diatomic nature of O(2), the sequence of the oxidation and reduction reactions, and other salient features. The catalytic reactions involved in the oxidation of ascorbic acid by plant ascorbate oxidase, ceruloplasmin, and Cu(II) are compared. Finally the substrate specificity, inhibitory control, and the detailed mechanism of the oxidase activity of ceruloplasmin are summarized.
J Gen Physiol 1965 Sep
PMID:Copper proteins and oxygen. Correlations between structure and function of the copper oxidases. 428 28

A particulate tyrosinase has been extracted and purified from tentacles of the sea anemone Metridium senile. The purified enzyme had properties in common with both mushroom and vertebrate tyrosinase and catalyzed three different reactions: oxidation of catechols, hydroxylation of L-tyrosine with L-dopa as cofactor and 5-hydroxylation of L-dopa. 5-Hydroxylation of L-dopa by an animal tyrosinase has not been reported earlier. The reaction could be analyzed under reducing conditions when the much faster oxidation of L-dopa to dopaquinone was inhibited. The conditions required for the accumulation of L-dopa and 5-hydroxydopa observed in vivo in tentacles of Metridium are discussed.
Gen Pharmacol 1984
PMID:Enzymatic 5-hydroxylation of L-dopa by a tyrosinase isolated from the sea anemone Metridium senile. 614 65

In two separate studies a BclI-generated DNA fragment coding for the enzyme tyrosinase, responsible for melanin synthesis, was cloned from Streptomyces antibioticus DNA into two SLP1.2-based plasmid vectors (pIJ37 and pIJ41) to generate the hybrid plasmids, designated pIJ700 and pIJ701, using S. lividans 66 as the host. The fragment (1.55 kb) was subcloned into the multicopy plasmid pIJ350 (which carries thiostrepton resistance and has two non-essential BclI sites) to generate four new plasmids (pIJ702-pIJ705) with the tyrosinase insert located in either orientation at each site. All six plasmids conferred melanin production (the Mel+ phenotype) on their host. As in the S. antibioticus parent, strains of S. lividans carrying the gene specifying tyrosinase synthesis possessed an enzyme activity which was inducible. Most of the tyrosinase activity was secreted during growth of S. antibioticus; in contrast, the majority remained intracellular in the S. lividans clones. The specific activity of the induced tyrosinase activity (intracellular) was higher (up to 36-fold) when the gene was present on the multicopy vector in comparison with its location on the low copy plasmids, pIJ700 or pIJ701, or in S. antibioticus. Restriction mapping of the tyrosinase fragment in pIJ702 revealed endonuclease cleavage sites for several enzymes, including single sites for BglII, SphI and SstI that are absent from the parent vector (pIJ350). Insertion of DNA fragments at any one of these sites abolished the Mel+ phenotype. The results indicate that pIJ702 is a useful cloning vector with insertional inactivation of the Mel+ character as the basis of clone recognition.
J Gen Microbiol 1983 Sep
PMID:Cloning and expression of the tyrosinase gene from Streptomyces antibioticus in Streptomyces lividans. 631 61

1. Harding-Passey mouse-melanoma tyrosinase (EC 1.14.18.1) is inhibited during L-3,4-dihydroxyphenylalanine oxidation by reaction products. L-3,4-dihydroxyphenyl 3-[14C]alanine oxidation products bind to the enzyme, as demonstrated by gel electrophoresis and radioactivity measurements. 2. The enzyme interacts with indoles and oxidizes dopamine and norepinephrine. 3. L-epinephrine activates tyrosinase at non hormonal concentrations and bovine serum albumin protects the enzyme from auto-inhibition. 4. The inhibition of the Harding-Passey mouse-melanoma tyrosinase, during substrate oxidation, is very similar to that of mushroom enzyme.
Gen Pharmacol 1983
PMID:Harding-passey mouse-melanoma tyrosinase inactivation by reaction products and activation by L-epinephrine. 640 91

The sporulating wild type of Streptomyces reticuli produces the pigment melanin. Though the ability to synthesize tyrosinase is frequently lost, it was demonstrated, that the structural gene coding for this enzyme is not located on the extrachromosomal DNA of the wild type strain or melanin-positive variants. Melanin negative variants were found to have lost this gene and to contain amplified nucleotide sequences within their genomes.
Mol Gen Genet 1983
PMID:Deletion and amplification of DNA sequences in melanin-negative variants of Streptomyces reticuli. 640 51


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