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Characterization of a metalloprotease from psychrophilic Xanthomonas maltophilia

Rosa Margesin, Franz Schinner
DOI: http://dx.doi.org/10.1111/j.1574-6968.1991.tb04538.x 257-261 First published online: 1 April 1991


An extracellular protease from psychrophilic Xanthomonas maltophilia isolated from alpine environment was purified and characterized. In spite of a comparable growth at 10°C and 20°C, protease excretion occured only at 10°C. The enzyme was a 21-kDa protein with an isoelectric point higher than 9.5. The optimum pH and temperature for azocaseinolytic activity were 8.0 and 50°C respectively. The enzyme was stable up to 40°C but became inactive after 10 min at 60°C. The energy of activation was comparable to that of enzymes from mesophilic sources. Sensitivity to EDTA indicates that X. maltophilia protease is a metalloprotease.

Key words
  • Xanthomonas maltophilia
  • Metalloprotease
  • Psychrophilic
  • Alpine environment

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