Improved Identification of Protease Cleavage Sites by In-gel Reductive Dimethylation.

A critical step in the functional characterization of proteases is the identification of physiologically relevant substrates, which often starts with a collection of candidate proteins. To test these candidates and identify specific processing sites, in vitro cleavage assays are typically used, followed by polyacrylamide gel electrophoresis (SDS-PAGE) to separate and visualize the cleavage products. For the identification of cleavage sites, the sequences at the N- or C-terminal ends of the cleavage products need to be identified, which is the most challenging step in this procedure.

Identification of Cognate Protease/Substrate Pairs by Use of Class-Specific Inhibitors.

Many proteins are regulated post-translationally by proteolytic processing. This includes plant signaling peptides that are proteolytically released from larger precursor proteins. The proteases involved in the biogenesis of signaling peptides and in regulation of other proteins by limited proteolysis are largely unknown.

Processing of a plant peptide hormone precursor facilitated by posttranslational tyrosine sulfation.

Most peptide hormones and growth factors are matured from larger inactive precursor proteins by proteolytic processing and further posttranslational modification. Whether or how posttranslational modifications contribute to peptide bioactivity is still largely unknown. We address this question here for TWS1 (Twisted Seed 1), a peptide regulator of embryonic cuticle formation in .