Complex formation between mushroom tyrosinase and Manduca dopachrome isomerase
| Autor: | Timothy Scott, Manickam Sugumaran, Kaliappan Nellaiappan, Chamanie Amaratunga |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Stereochemistry
Tyrosinase Clinical Biochemistry Plant Science Isomerase chemistry.chemical_compound Manduca Enzyme Stability Concanavalin A Animals Isomerases chemistry.chemical_classification Melanins Chromatography biology Monophenol Monooxygenase Basidiomycota Sepharose Cell Biology biology.organism_classification Quinone methide Intramolecular Oxidoreductases Molecular Weight Kinetics Enzyme chemistry Biochemistry Manduca sexta Dopachrome Metabolon Isoelectric Focusing Agronomy and Crop Science Developmental Biology Protein Binding |
| Zdroj: | Pigment cell research. 8(4) |
| ISSN: | 0893-5785 |
| Popis: | Melanin biosynthesis in animals is initiated by the ubiquitously present tyrosinase and is aided by dopachrome isomerase. We have characterized a novel dopachrome isomerase (decarboxylating) from the hemolymph of Manduca sexta that generates a new quinone methide intermediate during melanogenesis (Sugumaran, M. and Semensi, V. (1991) J. Biol. Chem. 266, 6073-6078). This enzyme has the ability to form a complex with mushroom tyrosinase as judged by a number of physicochemical studies. The isomerase exhibited a marked inhibitory effect on tyrosinase and tyrosinase reciprocated by inhibiting the isomerase. While the isomerase showed no activity toward preformed dopaminechrome, it readily influenced the stability of dopaminechrome generated in situ by tyrosinase. Moreover, mushroom tyrosinase, which lacked specific binding to Concanavalin A Sepharose column, after complexing with the isomerase exhibited binding to this column. The complex formation also affected the pI value as well as mobility on a size exclusion column of these enzymes. Enzymes executing sequential metabolic transformation are known to form complexes called metabolons. Based on these above studies, it is concluded that both the enzymes involved in insect melanogenic pathway--phenoloxidase and dopachrome isomerase--are able to form a metabolon complex. |
| Databáze: | OpenAIRE |
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