Cysteine reactivity profiling

Fig. 12 isoTOP-ABPP for cysteine reactivity profiling. R[high][iow] is the ratio of labeling between heavy and light variants... 

Weerapana E, Wang C, Simon GM et al (2010) Quantitative reactivity profiling predicts functional cysteines in proteomes. Nature 468 790-795... 

Greengauz-Roberts, O., Sloppier, H Nomura, S., Yamaguchi, H Goldenring, J. R., Podolsky, R. H., Lee, J. R., and Dynan, W.S. (2005) Saturation labeling with cysteine-reactive cyanine fluorescent dyes provides increased sensitivity for protein expression profiling of laser-microdissected clinical specimens. 

The greatly increased nucleophilicity of the catalytic serine distinguishes it from all other serine residues and makes it an ideal candidate for modification via activity-based probes [58]. Of the electrophilic probe types to profile serine hydrolases, the fluorophosphonate (FP)-based probes are the most extensively used and were first introduced by Cravatt and coworkers [38, 39]. FPs have been well-known inhibitors of serine hydrolases for over 80 years and were first applied as chemical weapons as potent acetylcholine esterase inhibitors. As FPs do not resemble a peptide or ester substrate, they are nonselective towards a particular serine hydrolase, thus allowing the entire family to be profiled. FPs also show minimal cross-reactivity with other classes of hydrolases such as cysteine-, metallo-, and aspartylhydrolases [59]. Furthermore, FP-based probes react only with the active serine hydrolase, and not the inactive zymogen, allowing these probes to interact only with functional species within the proteome [59]. Extensive use of this probe family has demonstrated their remarkable selectivity for serine hydrolases and resulted in the identification of over 100 distinct serine hydrolases... 

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