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Physiology and Biochemistry

Purification of an Endo-β-1,4 Galactanase Produced by Sclerotinia sclerotiorum: Effects on Isolated Plant Cell Walls and Potato Tissue. Wolfgang D. Bauer, Research Associate, Department of Plant Pathology, Cornell University, Ithaca, NY 14853, Current address of senior author: Charles F. Kettering Research Laboratory, Yellow Springs, OH 45387; D. F. Bateman(2), and Catherine H. Whalen(3). (2)(3)Professor and Chairman, and Research Technician, respectively, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 67:862-868. Accepted for publication 24 February 1977. Copyright 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-862.

Sclerotinia sclerotiorum produces an endo-β-1,4 galactanase when grown in a liquid mineral salts medium supplemented with 2.0 g of Difco yeast extract and 2.0 g or 6.0 g D-galactose per liter. This enzyme was purified by CM Sephadex ion exchange chromatography and by Sephadex G-50 and G-75 gel filtration. The purified enzyme has an isoelectric point of 8.3, a pH optimum of approximately 4.5, and a molecular weight of 22,000 to 24,000 daltons. This enzyme, free of endopolygalacturonase or pectic lyase activity, readily solubilized substantial amounts of carbohydrate including a major portion of the galactan component from isolated sycamore and potato cell walls. However, endo-β-1,4 galactanase, at a concentration of 0.3 units/ml, did not cause maceration of potato tuber tissue disks during a 20-hr exposure at pH 5.0, even though some galactose was released from the tissue.