Tyrosinases, which are widely distributed among animals, plants and fungi, are involved in many biologically essential functions, including pigmentation, sclerotization, primary immune response and host defence. In the present study, we present a structural and physicochemical characterization of two new tyrosinases from the crustaceans Palinurus elephas (European spiny lobster) and Astacus leptodactylus (freshwater crayfish). In vivo, the purified crustacean tyrosinases occur as hexamers composed of one subunit type with a molecular mass of approx. 71kDa. The tyrosinase hexamers appear to be similar to the haemocyanins, based on electron microscopy. Thus a careful purification protocol was developed to discriminate clearly between tyrosinases and the closely related haemocyanins. The physicochemical properties of haemocyanins and tyrosinases are different with respect to electronegativity and hydrophobicity. The hexameric nature of arthropod tyrosinases suggests that these proteins were the ideal predecessors from which to develop the oxygen-carrier protein haemocyanin, with its allosteric and co-operative properties, later on.
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April 2003
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Research Article|
April 15 2003
Tyrosinases from crustaceans form hexamers
Elmar JAENICKE;
Elmar JAENICKE
Institut für Molekulare Biophysik, Johannes Gutenberg Universität Mainz, Jakob Welder Weg 26, D-55128 Mainz, Germany
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Heinz DECKER
Heinz DECKER
1
Institut für Molekulare Biophysik, Johannes Gutenberg Universität Mainz, Jakob Welder Weg 26, D-55128 Mainz, Germany
1To whom correspondence should be addressed (e-mail decker@biophysik.biologie.uni-mainz.de).
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Publisher: Portland Press Ltd
Received:
July 05 2002
Revision Received:
November 08 2002
Accepted:
December 04 2002
Accepted Manuscript online:
December 04 2002
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London ©2003
2003
Biochem J (2003) 371 (2): 515–523.
Article history
Received:
July 05 2002
Revision Received:
November 08 2002
Accepted:
December 04 2002
Accepted Manuscript online:
December 04 2002
Citation
Elmar JAENICKE, Heinz DECKER; Tyrosinases from crustaceans form hexamers. Biochem J 15 April 2003; 371 (2): 515–523. doi: https://doi.org/10.1042/bj20021058
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