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The PGM3 gene encodes the major phosphoribomutase in the yeast Saccharomyces cerevisiae
Author(s) -
Walther Thomas,
Baylac Audrey,
Alkim Ceren,
Vax Amélie,
Cordier Hélène,
François Jean Marie
Publication year - 2012
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2012.09.042
Subject(s) - ribose , saccharomyces cerevisiae , biochemistry , yeast , biology , phosphate , mutant , enzyme , nucleotide , genetics , gene
The phosphoglucomutases (PGM) Pgm1, Pgm2, and Pgm3 of the yeast Saccharomyces cerevisiae were tested for their ability to interconvert ribose‐1‐phosphate and ribose‐5‐phosphate. The purified proteins were studied in vitro with regard to their kinetic properties on glucose‐1‐phosphate and ribose‐1‐phosphate. All tested enzymes were active on both substrates with Pgm1 exhibiting only residual activity on ribose‐1‐phosphate. The Pgm2 and Pgm3 proteins had almost equal kinetic properties on ribose‐1‐phosphate, but Pgm2 had a 2000 times higher preference for glucose‐1‐phosphate when compared to Pgm3. The in vivo function of the PGMs was characterized by monitoring ribose‐1‐phosphate kinetics following a perturbation of the purine nucleotide balance. Only mutants with a deletion of PGM3 hyper‐accumulated ribose‐1‐phosphate. We conclude that Pgm3 functions as the major phosphoribomutase in vivo.