Proteolytic catabolite inactivation in Saccharomyces cerevisiae

Area of Science:

• * Molecular biology
• * Biochemistry
• * Yeast metabolism

Background:

• * Saccharomyces cerevisiae exhibits catabolite repression and inactivation of enzymes in response to fermentable sugars.
• * Catabolite inactivation affects a specific subset of enzymes, distinct from those under catabolite repression.
• * Understanding these regulatory mechanisms is crucial for comprehending yeast metabolic adaptability.

Purpose of the Study:

• * To identify enzymes subject to catabolite inactivation in Saccharomyces cerevisiae.
• * To elucidate the proteolytic mechanisms underlying catabolite inactivation for specific enzymes.
• * To summarize current knowledge on the conditions, mechanisms, and biological significance of this inactivation process.

Main Methods:

• * Review and summarization of existing literature on catabolite inactivation in Saccharomyces cerevisiae.
• * Analysis of proteolytic mechanisms for five key enzymes: cytoplasmic malate dehydrogenase, aminopeptidase I, fructose-1,6-bisphosphatase (FBPase), phosphoenolpyruvate carboxykinase, and isocitrate lyase.
• * Focus on enzymes involved in gluconeogenesis and their regulation.

Main Results:

• * Catabolite inactivation was observed in a specific group of enzymes in Saccharomyces cerevisiae.
• * The mechanism of inactivation for five enzymes was identified as proteolytic.
• * These five enzymes include key players in gluconeogenesis (except aminopeptidase I).

Conclusions:

• * Proteolytic inactivation is a significant mechanism regulating key gluconeogenic enzymes in Saccharomyces cerevisiae.
• * This process is essential for metabolic adaptation, deactivating gluconeogenesis when fermentable sugars are present.
• * The findings highlight the intricate control of metabolic pathways in response to nutrient availability.