The subset of the proteome that contains enzymes in their catalytically active form can be interrogated by using probes tar-geted towards individual specific enzymes. A subset of such enzymes are proteases that are frequently studied with activity-based probes, small inhibitors equipped with a detectable tag, commonly a fluorophore. Due to the spectral overlap of these commonly used fluorophores, multiplex analysis becomes limited. To overcome this, we developed a series of protease-selective lanthanide-labeled probes compatible with mass cytometry giving us the ability to monitor the activity of multiple proteases in parallel. Using these probes we were able to identify the distribution of four proteases with different active site geometries in three cell lines and peripheral blood mononuclear cells. This provides a framework for the use of mass cytome-try for multiplexed enzyme activity detection.

中文翻译：

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使用质谱仪兼容的基于活性的探针对蛋白水解酶进行多重探测。

可以通过使用针对单个特定酶的探针来询问含有催化活性形式酶的蛋白质组子集。这类酶的一个子集是蛋白酶，经常用基于活性的探针研究，小抑制剂配备可检测的标签，通常是荧光团。由于这些常用荧光团的光谱重叠，多重分析变得有限。为了克服这个问题，我们开发了一系列与质谱流式细胞仪兼容的蛋白酶选择性镧系元素标记探针，使我们能够同时监测多种蛋白酶的活性。使用这些探针，我们能够鉴定具有不同活性位点几何形状的四种蛋白酶在三种细胞系和外周血单核细胞中的分布。