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Updated: Aug 15, 2026

Growth-based Determination and Biochemical Confirmation of Genetic Requirements for Protein Degradation in Saccharomyces cerevisiae
Published on: February 16, 2015
Inactivation and degradation of yeast glucose-6-phosphate dehydrogenase selectively modified by pyridoxal-5-phosphate
Abstract:
Modification by pyridoxal-5-phosphate of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) purified from Saccharomyces cerevisiae produces an inactivation effect, partially reversible by dilution in the presence of substrates. Spectroscopic analysis of the enzyme pyridoxal-5-phosphate complex reduced with NaBH4 provides the values expected for the binding of the aldehydic group to Lys residue. One Lys residue appears to be responsible for the observed enzyme inactivation, and the presence of the phosphate group is required for the effect. Besides the change of activity, the binding of pyridoxal-5-phosphate to the enzyme causes an increase in susceptibility to degradation by the intracellular yeast proteinase A at pH 7.6.
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