Influence of Acidic Exopolysaccharide of Xanthomonas campestris IBPM 124 on the Kinetic Parameters of Extracellular Bacteriolytic Enzymes

O. A. Stepnaya^*, L. P. Ryazanova, V. I. Krupyanko, and I. S. Kulaev

Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia; fax: (095) 956-3370; E-mail: kulaev@ibpm.serpukhov.su

^* To whom correspondence should be addressed.

Received October 24, 2000; Revision received February 25, 2001

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Interactions of a negatively charged exopolysaccharide of Xanthomonas campestris IBPM 124 with its extracellular enzymes (muramidase, endopeptidase, and neutral phosphatase) and also with egg lysozyme, lysostaphin, muramidase of Streptomyces globisporus, and a bacteriolytic enzyme complex of Streptomyces albus were studied. All these enzymes were positively charged under the conditions of their maximal activity. It was shown that interaction of the acidic exopolysaccharide from X. campestris with these enzymes changed their kinetic parameters. The change was either positive (increase in reaction rate) or negative (decrease in reaction rate) and depended on the enzyme and type of substrate cleaved. Due to such interactions, the acidic exopolysaccharide secreted by X. campestris into the environment not only retained and transported positively charged exoenzymes into the near-cellular space, but also regulated their activity.

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KEY WORDS: Xanthomonas campestris, lysoamidase, bacteriolytic enzymes, polysaccharide, interaction

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