Investigating redox regulation of protein tyrosine phosphatases using low pH thiol labeling and enrichment strategies coupled to MALDI-TOF mass spectrometry.

A central feature of the protein tyrosine phosphatase (PTP) catalytic mechanism is an attack of the substrate's phosphate moiety by a thiolate ion in the signature CX5R motif. In addition to being an effective nucleophile in this form, the thiolate ion is also susceptible to reversible redox regulation. This attribute permits temporal inhibition of PTP activities, which affects numerous cellular processes utilizing kinase-mediated signal propagation.

Profiling phlorotannins in brown macroalgae by liquid chromatography-high resolution mass spectrometry.

Introduction: Phlorotannins, phenolic compounds produced exclusively by Phaeophyceae (brown algae), have recently been associated with a wide variety of beneficial bioactivities. Several studies have measured the total phenolic content in extracts from various species, but little characterisation of individual phlorotannin components has been demonstrated.

Objective: The purpose of this study was to develop a liquid chromatography-mass spectrometry (LC-MS) based method for rapid profiling of phlorotannins in brown algae.