ACCELERATED PUBLICATION High Molecular Mass Exopolyphosphatase from the Cytosol of the Yeast Saccharomyces cerevisiae Is Encoded by the PPN1 Gene

Inorganic polyphosphate is a source of energy, performs regulatory functions, and plays an important role in adaptation of yeast and other microbial cells to changing environment The aim of this study was to identify the gene encoding the high molecular mass exopolyphosphatase of the cytosol of S. cerevisiae. MATERIALS AND METHODS Purification of high molecular mass exopolyphosphatase. Cells of S. cerevisiae VKM Y-1173 were grown in phosphate surplus conditions as described earlier Hydrolysis of polyphosphate by purified exopolyphosphatase. The exopolyphosphatase activity was assayed at 30°C by measuring the rate of P i accumulation Mass spectrometry. The purified exopolyphosphatase was subjected to electrophoresis in 12.5% poly- ISSN 0006-2979, Biochemistry (Moscow), 2006, Vol. 71, No. 9, pp. 975-977. © Pleiades Publishing, Inc., 2006. Published in Russian in Biokhimiya, 2006, Vol. 71, No. 9, pp. 1198-1201 On-Line Papers in Press, as Manuscript BM06-086, June 11, 2006. Abstract-It has been shown that the high molecular mass exopolyphosphatase localized in cytosol of the yeast Saccharomyces cerevisiae is encoded by the PPN1 gene. This enzyme is expressed under special culture conditions when stationary phase cells are passing on to new budding on glucose addition and phosphate excess. The enzyme under study releases orthophosphate from the very beginning of polyphosphate hydrolysis

Amorphous Silica Containers for Germanium Ultrapurification by Zone Refining

We have studied the wetting behavior of molten germanium on silica ceramics and amorphous silica coatings in vacuum at a pressure of 1 Pa and a temperature of 1273 K. The results demonstrate that the wetting of rough surfaces of ceramic samples and coatings by liquid Ge is significantly poorer than that of the smooth surface of quartz glass. The contact angle of polished glass is ~100°, and that of the ceramics and coatings increases from 112° to 137° as the total impurity content of the material decreases from 0.120 to 1 × 10–3 wt %. Using experimental contact angle data, we calculated the work of adhesion of molten Ge to the materials studied. Its value for the surface of the ceramics and coatings decreases from 0.45 to 0.20 J/m2 with decreasing impurity content, whereas the work of adhesion to a smooth glass surface is 0.55 J/m2. We have fabricated fused silica test containers coated with high-purity amorphous silica. Using horizontal zone refining, we obtained germanium samples with a carrier concentration difference on the order of 1011 cm–3

biochemistry of inorganic polyphosphates

I.S. Kulaev, V.M. Vagabov, T.V. Kulakovskaya.x, 277 p. : ill. ; 25 cm

Amorphous Silica Containers for Germanium Ultrapurification by Zone Refining

We have studied the wetting behavior of molten germanium on silica ceramics and amorphous silica coatings in vacuum at a pressure of 1 Pa and a temperature of 1273 K. The results demonstrate that the wetting of rough surfaces of ceramic samples and coatings by liquid Ge is significantly poorer than that of the smooth surface of quartz glass. The contact angle of polished glass is ~100°, and that of the ceramics and coatings increases from 112° to 137° as the total impurity content of the material decreases from 0.120 to 1 × 10–3 wt %. Using experimental contact angle data, we calculated the work of adhesion of molten Ge to the materials studied. Its value for the surface of the ceramics and coatings decreases from 0.45 to 0.20 J/m2 with decreasing impurity content, whereas the work of adhesion to a smooth glass surface is 0.55 J/m2. We have fabricated fused silica test containers coated with high-purity amorphous silica. Using horizontal zone refining, we obtained germanium samples with a carrier concentration difference on the order of 1011 cm–3