Description Application Photo-activatable sterol probe for the bioorthogonal tagging and enrichment of sterol-binding biomolecules. This sterol probe contains an intact steroid core structure bearing a diazirine UV-activatable cross-linking group, as well as an alkyne group for click-chemistry mediated adduction of reporter and affinity tags. The probes are cell-permeable, allowing for in situ labeling of biomolecules in live cells, as well as in cell extracts in vitro. Packaging 5 mg in glass bottle Other Notes Handle the probes in amber vessels under dim ambient light whenever possible. Aqueous solutions of probes complexed to methyl-β-cyclodextrin (20:1 = m-β-CD:probe molar ratio, 5-20 μM probe) permeate cultured cells in complete serum-containing medium within 30 minutes at 37°C and are cross-linked using near-UV (365 nm) light for 3-10 minutes. Cells can then be harvested and lysed, fractionated or otherwise processed. Click chemistry (Cu(I)-catalyzed 1,3-dipolar cycloaddition of the alkyne with an azide reporter tag such as a fluorophore or biotin, products 760765 or 762024) can be performed in protein samples in PBS for gel-visualization of probe-labeling, MS-based proteomics analysis of probe-mediated affinity enrichments or western blot analysis.