生物素-XX 酪胺(Biotin-XX-Tyramide,又称 Biotin-XX-Phenol;BxxP)是邻近标记探针生物素酪胺(Biotin-Tyramide,又称 Biotin-Phenol;BP)的一种细胞膜不透性衍生物,具有较长的极性聚酰胺连接臂。与 BP 类似,BxxP 可在辣根过氧化物酶(HRP)和过氧化氢(H₂O₂)作用下实现生物素标记。与 BP 不同,BxxP 不易穿透完整细胞膜,适用于选择性标记细胞表面蛋白,而非细胞内蛋白。
Biotin-XX-tyramide (biotin-XX-phenol; BxxP) is a membrane-impermeant variant of the proximity labeling probe biotin-tyramide (biotin-phenol; BP), containing a long, polar polyamide linker. Similar to BP, BxxP enables biotinylation in the presence of HRP and H₂O₂. Unlike BP, BxxP has reduced permeability across intact cell membranes, allowing selective labeling of cell-surface rather than intracellular proteins.