Page 173 - The Biochemistry of Inorganic Polyphosphates

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WU095/Kulaev
WU095-08
Yeast 157
(a)
100 2 1.5
Exopolyphosphatase activity (% of total activity) 75 1 0.5 Dry biomass (g l −1 )
50

25

0 0
0 1 2 3 4 5 6 7 8 13
Time of growth (h)

(b)
100 2

Exopolyphosphatase activity (% of total activity) 75 1.5 biomass (g l −1 ) Dry

50
1

25
0.5
0 0
0 1 2 3 4 5 6 7 8 9 10 31
Time of growth (h)

Figure 8.22 The activities of exopolyphosphatases 1 ( ) and 2 ( ) in the cytosol fraction of
Saccharomyces cerevisiae during the process of growth (•) at a low initial cell density without re-
inoculation: (a) complete Reader medium; (b) P i -limited medium. The cytosol fraction was subjected
to gel filtration on a Sephacryl S-300 column. The exopolyphosphatase activities were estimated
separately in the fractions corresponding to the molecular masses of ∼ 40 kDa (exopolyphosphatase
1) and ∼ 830 kDa (exopolyphosphatase 2).

8.10.6 The Effects of other Conditions on the Polyphosphate
Content in Yeast Cells

The dependence of the PolyP content in yeast on the carbon and nitrogen sources has not
been studied systematically. In some yeasts, which were able to grow on alkanes, much
more rapid accumulation of PolyP (2–3 times) during growth on these carbon sources was
observed when compared with growth on glucose (Levchuk et al., 1969; Grigor’eva et al.,
1973). In contrast, PolyP synthesis with ethanol as an energy source was slower than with
glucose in the cells of S. cerevisiae and K. marxianus (Schuddemat et al., 1989a).
When young S. cerevisiae cells were incubated in Tris buffer, at pH 7.5, with 5 % of
ethanol, a rapid breakdown of the ‘NMR-visible’ PolyP into smaller fragments occurred