Biological function of ;pathogenesis-related' proteins: four PR proteins of tobacco have 1,3-beta-glucanase activity.
Three of the ten acidic ;pathogenesis-related' (PR) proteins known to accumulate in Nicotiana tabacum cv Samsun NN reacting hypersensitively to tobacco mosaic virus, namely -O, -N and -2, have been shown to have 1,3-beta-glucanase (EC 3.2.1.39) activity. By using sera raised against each protein purified to homogeneity close serological relationships have been demonstrated between the three proteins. The same specific sera cross-reacted with a basic protein which is also a 1,3-beta-glucanase induced by virus infection and which can be considered as a new basic pathogenesis-related protein of tobacco. Protein PR-O and the basic 1,3-beta-glucanase display about the same specific enzymatic activity, i.e. 50-fold and 250-fold higher than specific activities of proteins PR-N and -2 respectively.
Kauffmann
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Institut de Biologie Moléculaires des Plantes, 12, rue du Général Zimmer, 67000 Strasbourg, France.
Legrand
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Geoffroy
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P
Fritig
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