SUC2

SUC2 is a gene in the yeast Saccharomyces cerevisiae that encodes invertase, an enzyme responsible for hydrolyzing sucrose into glucose and fructose. The enzyme is secreted into the extracellular space or anchored to the cell surface, allowing the organism to utilize sucrose present in the environment as a carbon source. The SUC2-encoded invertase is an acid invertase and belongs to the glycoside hydrolase family 32. The protein product contains an N-terminal signal sequence that directs secretion.

Regulation of SUC2 expression is tied to the carbon source available. In high glucose conditions, SUC2 expression is repressed by carbon catabolite repression mechanisms, while in low glucose and in the presence of sucrose, SUC2 is induced. The regulation involves key signaling pathways that respond to glucose levels, enabling the cell to switch between preferred and non-preferred carbon sources.

Biological role and metabolism: By secreting invertase, S. cerevisiae can hydrolyze extracellular sucrose into glucose and fructose, which are then taken up by hexose transporters. This capability is advantageous in environments rich in sucrose, such as fruits or grape must, and contributes to fermentation performance in mixed-sugar ecosystems.

Genetic and research context: SUC2 is the principal invertase gene in S. cerevisiae and has long served as a model in genetics and cell biology for studies of secretion, metabolism, and gene regulation. Invertase genes and activity are conserved in many yeast and fungal species, reflecting a common strategy for accessing sucrose as a carbon source.