The Content and Chain Length of Polyphosphates from Vacuoles of Saccharomyces cerevisiae VKM Y-1173

L. V. Trilisenko^*, V. M. Vagabov, 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: LVAT@ibpm.serpukhov.su

^* To whom correspondence should be addressed.

Received May 14, 2001

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The content of inorganic polyphosphates (polyP) in vacuoles of the yeast Saccharomyces cerevisiae is ~15% of the total cellular polyP. Over 80% of the vacuole polyP are in an acid-soluble fraction. It was first established by ³¹P-NMR spectroscopy that a polymeric degree (n) of two subfractions obtained by precipitation with Ba²⁺ in succession at pH 4.5 and 8.2 was approximately 20 ± 5 and 5 ± 2 residues of ortho-phosphoric acid, respectively. Under a deficit of phosphate (P_i) in the cultivation medium, the polyP content in vacuoles decreased ~7-fold with the same drastic reduction of their content in the cell. Unlike intact yeast cells, where polyP overcompensation is observed after their transfer from phosphate-free to phosphate-containing medium, the vacuoles do not show this effect. The data indicate the occurrence of special regulatory mechanisms of polyP synthesis in vacuoles differing from those in the whole cell.

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KEY WORDS: yeast, protoplasts, vacuoles, overcompensation, polyphosphates, exopolyphosphatase

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