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Physiology and Biochemistry

α-l-Arabinofuranosidase from Sclerotinia sclerotiorum: Purification, Characterization, and Effects on Plant Cell Walls and Tissue. C. Jacyn Baker, Department of Plant Pathology, Cornell University, Ithaca, New York 14853; Catherine H. Whalen(2), Ruth Z. Korman(3), and Durward F. Bateman(4). (2)(3)(4)Department of Plant Pathology, Cornell University, Ithaca, New York 14853. Phytopathology 69:789-793. Accepted for publication 2 February 1979. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-789.

Sclerotinia sclerotiorum produced α-l-arabinofuranosidase when grown at 25 C on a medium of mineral salts containing 0.4% l-arabinose plus 0.2% Difco yeast extract. Enzyme in filtrates from 14-day-old cultures was concentrated and dialyzed by Amicon ultrafiltration. The specific activity of the α- l-arabinofuranosidase was increased 26 × by a four step procedure: (i) preparative electrofocusing in granulated gel using ampholytes with a pH of 7–9; (ii) column ion-exchange chromatography (CM-Sephadex [C-50]) in 20 mM sodium acetate at pH 5.0; and (iii, iv) two cycles of gel filtration on Ultrogel (AcA 54) in 72 mM phosphate buffer at pH 7.0 containing 100 mM NaCl. Purified α- l-arabinofuranosidase had a pH optimum of 4.0–4.5, a molecular weight of about 63,000 and a pI of about 7.5. This enzyme released arabinose from arabinan and from isolated cell walls of bean and rice. Highly active preparations of this α- l-arabinofuranosidase failed to macerate potato tuber or cucumber endocarp tissue.