African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12269

Full Length Research Paper

Purification and characterization of a peroxidase present in xilopodium exsudates of umbu plants (Spondias tuberosa A.)

Marcio dos Santos Teixeira Pinto*
  • Marcio dos Santos Teixeira Pinto*
  • Universidade Federal do Tocantins (UFT), Curso de Engenharia de Bioprocessos e Biotecnologia. Rua Badejos, chacaras 69 a 72, lote 07, Zona Rural. Caixa Postal 66. CEP: 77.402-970. Gurupi, TO, Brasil.
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Juliana Martins Ribeiro
  • Juliana Martins Ribeiro
  • Laboratorio de Biotecnologia, Embrapa Semiarido (CPATSA), BR 428, Km 152, Zona Rural. Caixa Postal 23, CEP 56302-970, Petrolina, PE, Brasil.
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Francisco Pinheiro de Araujo
  • Francisco Pinheiro de Araujo
  • Laboratorio de Biotecnologia, Embrapa Semiarido (CPATSA), BR 428, Km 152, Zona Rural. Caixa Postal 23, CEP 56302-970, Petrolina, PE, Brasil.
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Natoniel Franklin de Melo
  • Natoniel Franklin de Melo
  • Laboratorio de Biotecnologia, Embrapa Semiarido (CPATSA), BR 428, Km 152, Zona Rural. Caixa Postal 23, CEP 56302-970, Petrolina, PE, Brasil.
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Katia Valevski Sales Fernandes
  • Katia Valevski Sales Fernandes
  • Laboratorio de Quimica e Funcao de Proteinas e Peptideos, Centro de Biociencias e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Avenida Alberto Lamego, 2000 - Parque California, CEP: 28013-602, Campos dos Goytacazes, RJ, Brasil.
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  •  Received: 22 February 2015
  •  Accepted: 11 May 2015
  •  Published: 27 May 2015

Abstract

Umbu plants are drought resistant trees which are able to store water and several other substances into its adapted root, named xylopodium. The exsudate from xilopodium is a natural solution rich in salts, sugars and a little concentration of proteins. In this work, we report the purification of a peroxidase (POX) from umbu xilopodium exsudate by direct extraction from polyacrylamide electrophoresis gels. Umbu POX showed optimum activity at pHs around 6.0 to 7.0 and high thermal resistance after incubation at 70°C for 6 min. POX activity present in crude extracts was more heat-resistant than in its purified form. When assayed with metal ions, umbu POX activity was shown to be inhibited by Mn2+ and stimulated by Ca2+ and Mg2+; it was also inhibited by sodium azide (concentrations higher then 1 mM) and not inhibited by either EDTA or tropolone. POX Km values for guaiacol and methylcatechol substrates were 6.83 and 22.25, respectively. The enzyme is proposed to be a guaiacol peroxidase and was seen to be located at higher concentrations in the outermost layers of xylopodium tissue, such as the endoderm.

 

Key words: Root enzyme, tissue brownig, guaiacol peroxidase, oxidative metabolism.

Abbreviation

APX, Ascorbate peroxidase; CAT, catalase, GPX, guaiacol peroxidase; HRP, horseradish peroxidase; LiP, lignine peroxidase; POX, peroxidase; MnP, manganese peroxidase; SOD, superoxide dismutase.