SNAP-tag®, CLIP-tag™ and ACP/MCP-tag Substrate Selection Chart

NEB® offers a large selection of fluorescent labels (substrates) for SNAP-, CLIP-, ACP- and MCP-tag fusion proteins. SNAP-tag® substrates consist of a fluorophore conjugated to guanine or chloropyrimidine leaving groups via a benzyl linker, while CLIP-tag™ substrates consist of a fluorophore conjugated to a cytosine leaving group via a benzyl linker. These substrates will label their respective tags without the need for additional enzymes. Cell-permeable substrates (SNAP-Cell® and CLIP-Cell™) are suitable for both intracellular and cell-surface labeling, whereas non-cell-permeable substrates (SNAP-Surface® and CLIP-Surface™) are specific for fusion proteins expressed on the cell surface only.

ACP/MCP-tag substrates are conjugated to the phosphopantetheinyl moeity of Coenzyme A (CoA) and require a separate enzyme (ACP or SFP Synthase) for labeling. The labeling reaction is specific for fusion proteins expressed on the cell surface. The same substrates are used to label both the ACP- and the MCP-tags; specificity is determined by the synthase used for labeling.