Ac4ManNDAz is a cell-permeable photocrosslinking probe that is a precursor to photocrosslinked sialic acid, which attaches to cell surface α2-6-conjugated sialic acid and produces photocrosslinking via sialic acid.

Instructions
1. Prepare a culture medium containing Ac4ManNDAz (usually add a specific concentration of Ac4ManNDAz, such as 20–100 µM, adjusted according to experimental requirements).
2. Expose cells to the culture medium containing Ac4ManNDAz and incubate for a certain period of time (usually 24–48 hours) to allow the probe to be incorporated into the glycoprotein synthesis pathway.
3. UV cross-linking: Collect cells treated with Ac4ManNDAz and wash with PBS or appropriate buffer; expose cells to UV light of a specific wavelength (usually 365 nm) for an irradiation time optimized according to the experiment (e.g. 5–15 minutes); after cross-linking is completed, stop UV irradiation immediately to avoid nonspecific damage.
4. Subsequent analysis:
a. Lyse cells: Extract cell lysate with lysis buffer (e.g. RIPA buffer).
b. Detect glycoprotein interactions: Isolate and identify glycoproteins and their ligands incorporated with Ac4ManNDAz by co-immunoprecipitation, mass spectrometry or other methods.
c. Fluorescent labeling or chemical labeling (if a reporter group is attached to Ac4ManNDAz): used for observation or quantitative analysis.