Open AccessNuclear exopolyphosphatase of Saccharomyces cerevisiae is not encoded by the PPX1 gene encoding the major yeast exopolyphosphatase
Author(s) -
Lichko Lidia P,
Kulakovskaya Tatyana V,
Kulaev Igor S
Publication year - 2003
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2003.tb00146.x
Subject(s) - inorganic pyrophosphatase , saccharomyces cerevisiae , biology , pyrophosphatase , biochemistry , yeast , strain (injury) , mutant , nuclear gene , cytoplasm , gene , enzyme , mitochondrial dna , pyrophosphate , anatomy
Abstract Intact nuclei from a parental strain CRY and a PPX1‐mutant CRX of Saccharomyces cerevisiae were isolated and found to be essentially free of cytoplasmic, mitochondrial and vacuolar marker enzymes. The protein‐to‐DNA ratios of the nuclei were 22 and 30 for CRY and CRX nuclei, respectively. An exopolyphosphatase (exopolyPase) with molecular mass of ∼57 kDa and a pyrophosphatase (PPase) of ∼41 kDa were detected in the parental strain CRY. Inactivation of PPX1 encoding a major exopolyPase (PPX1) in S. cerevisiae did not result in considerable changes in the content and properties of nuclear exopolyPase as compared to the parental strain of S. cerevisiae . Consequently, the nuclear exopolyPase was not encoded by PPX1 . In the CRX strain, the exopolyPase was stimulated by bivalent metal cations. Co 2+ , the best activator, stimulated it by ∼2.5‐fold. The exopolyPase activity was nearly the same with polyphosphate (polyP) chain lengths ranging from 3 to 208 orthophosphate when measured with Mg 2+ . With Co 2+ , the exopolyPase activity increased along with the increase in polymerization degree of the substrate.