FucT-X Activators

Chemical activators for FucT-X, as illustrated in the table, include a variety of small molecules that influence the fucosylation process either by providing necessary substrates and cofactors or by modulating cellular pathways that lead to increased fucosylation activity. GDP-fucose is the direct substrate for FucT-X, and its intracellular concentration is a limiting factor for fucosylation reactions. Therefore, compounds that can increase the level of GDP-fucose, such as AMP and thymidine, through salvage pathways, directly contribute to the enhancement of FucT-X activity. Similarly, manganese(II) chloride provides essential cofactors that are crucial for the optimal function of fucosyltransferases.

In the broader scope of cellular metabolism, NAD+ plays a pivotal role in energy production and metabolic processes that indirectly support the activities of enzymes like FucT-X by ensuring a supply of precursors for GDP-fucose synthesis. Compounds that influence the production or availability of GDP-fucose, like galactose and ethanolamine, serve as substrates in the pathway leading to its synthesis, thereby modulating FucT-X activity. Furthermore, some compounds exert their effects by maintaining or enhancing the demand for fucosylation within the cell. For instance, Brefeldin A, by disrupting Golgi structure, can lead to a compensatory increase in glycosylation activities, which includes fucosylation. Deoxyfuconojirimycin, by inhibiting the breakdown of fucosylated oligosaccharides, indirectly promotes sustained or increased fucosylation activity. Additionally, leupeptin preserves the integrity of glycoproteins against protease degradation, indirectly supporting the demand for FucT-X's enzymatic function.