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

Tyrosinase (EC 1.14.18.1) is the enzyme essential to pigment formation in mammals; this enzyme is specifically localized in melanocytes, which occur primarily in the skin, hair bulbs, and eyes. Three hybridomas, TMH-1, TMH-2, and TMH-3, which produce monoclonal antibodies directed against tyrosinase, were obtained by fusion of SP2/0 myeloma cells and lymphocytes of rats hyperimmunized with purified melanosomal tyrosinase. These three monoclonal antibodies bound specifically to the mature, T4 form of tyrosinase, and did not bind to either of the precursor forms (T1 or T2) of the enzyme, which demonstrates that further posttranslational modifications of this enzyme occur which had not previously been detected. Epitope mapping studies have shown that at least two different immunologic determinants on tyrosinase are recognized by these antibodies. All three antibodies showed positive immunofluorescence staining of pigmented murine melanocytes from various sources, including B16 melanoma growing in vivo and in vitro, epidermal melanocytes, and retinal melanocytes. The antibodies did not cross-react with unpigmented cells, including K1735 amelanotic melanoma cells, albino murine skin or eye tissue, fibrosarcoma cells, rat fibroblasts, or epidermal keratinocytes. These monoclonal antibodies are sensitive, highly specific probes for pigmented mammalian melanocytes.
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PMID:Anti-T4-tyrosinase monoclonal antibodies--specific markers for pigmented melanocytes. 241 67

Tyrosinase (EC 1.14.18.1) is a monophenol oxidase responsible for the synthesis of the black pigment known as melanin. The tyrosinase gene (melA) is plasmid-encoded in many rhizobial species. In Rhizobium etli CFN42, the genetic location of melA in the symbiotic plasmid (p42d) and its RpoN-NifA regulation suggest an involvement in symbiosis. In this work, we analyzed the symbiotic phenotype of a streptomycin-resistant derivative of CFN42 (CE3), a melA mutant (SP2) and a complemented strain (SP66), demonstrating that melA inactivation reduced nodule formation rate and diminished total nodule number by 27% when compared to the CE3 strain. The nitrogen fixation capacity of the mutant strain was not affected. Also, in vitro assays were performed where the resistance of CE3, SP2 and SP66 strains to H(2)O(2) was evaluated; the melA mutant strain was consistently less resistant to peroxide. In another series of experiments, Escherichia coli W3110 strain expressing R. etli melA displayed enhanced resistance to p-hydroxybenzoic, vanillinic and syringic acids, which are phenolic compounds frequently found in the soil. Our results are the first to demonstrate a specific role for tyrosinase in R. etli: this enzyme is required during early symbiosis, apparently providing resistance against reactive oxygen species and phenolic compounds generated as part of the plant protective responses.
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PMID:Tyrosinase from Rhizobium etli is involved in nodulation efficiency and symbiosis-associated stress resistance. 1769 11