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[Polyphosphate kinase activity in yeast vacuoles]
Biokhimiia (Moscow, Russia)
|September 1, 1977
Summary
Polyphosphate kinase, an enzyme crucial for energy metabolism, was found in yeast vacuoles. This enzyme primarily synthesizes polyphosphates within vacuoles, playing a key role in cellular energy regulation.
Area of Science:
- Biochemistry
- Cell Biology
- Enzymology
Background:
- Polyphosphate kinase (ATP: Polyphosphate phosphotransferase EC 2.7.4.1) is a transferase enzyme.
- Polyphosphates are important energy storage molecules in yeast cells.
Purpose of the Study:
- To investigate the localization and activity of polyphosphate kinase in Saccharomyces carlsbergensis yeast.
- To understand the role of this enzyme in polyphosphate metabolism within yeast vacuoles.
Main Methods:
- Enzyme activity assays.
- Subcellular fractionation of yeast cells.
- Localization studies using yeast protoplasts and vacuoles.
Main Results:
- Polyphosphate kinase was detected primarily in the vacuoles of Saccharomyces carlsbergensis.
- The direct ATP: Polyphosphate phosphotransferase reaction occurs mainly in vacuoles, synthesizing polyphosphates from ATP.
- The reverse reaction's localization was not determined, but vacuolar activity of the direct reaction is significantly higher (19%) than in general yeast protoplasts (1%).
- Vacuolar polyphosphates are utilized for ATP synthesis during active cell wall component production.
Conclusions:
- Vacuoles are the primary site of polyphosphate synthesis catalyzed by polyphosphate kinase in yeast.
- The enzyme plays a critical role in managing vacuolar polyphosphate pools for energy production, particularly during periods of high metabolic demand.