Asp-N protease

New Recombinant Asp-N Mass Spec Protease: Improved Format and Reduced Price

Posted on by Gary Kobs

Asp-N is a endoproteinase hydrolyzes peptide bonds on the N-terminal side of aspartic residues. The native form is isolated from Pseudomonas fragi. The majority of vendors currently provide a commercial product that consists of 2µg of lyophilized material in a flat bottom vial, and sold for $175–200 US. Formatting such a small amount of material in flat bottom vial can lead to inconsistent resuspension of the protease. Inconsistent working concentrations will lead to non-reproducible data. The current high price also prohibits large-scale use.

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The new recombinant Asp-N protease is cloned from Stenotrophomonas maltophilia and expressed in E. coli. Recombinant Asp-N has similar amino acid cleavage specificity as compared to native Asp-N. Digestion of a yeast extract with native and recombinant Asp-N produces very similar results. Providing 10µg lyophilized material in V-shaped vial with a visible cake enables more consistent re-suspension resulting in reproducible data. Due to improved yields the list price is now approximately 40% less when compared to native enzyme.
Learn more about this new recombinant Asp-N protease.

Asp-N Protease: Applications Update

Posted on by Gary Kobs
TrypsinLysC Page 2

Asp-N, Sequencing Grade, is an endoproteinase that hydrolyzes peptide bonds on the N-terminal side of aspartic and cysteic acid residues: Asp and Cys. Asp-N activity is optimal in the pH range of 4.0–9.0. This sequencing grade enzyme can be used alone or in combination with trypsin or other proteases to produce protein digests for peptide mapping applications or protein identification by peptide mass fingerprinting or MS/MS spectral matching. It is suitable for  in-solution or in-gel digestion reactions.

The following references illustrate the use of Asp-N in recent publications:

Protein sequence coverage

  1. Jakobsson, M et al. (2013)  Identification and characterization of a novel Human Methyltransferase modulating Hsp70 protein function through lysine methylation. J. Biol. Chem. 288, 27752–63.
  2. Carroll, J. et. al. (2013) Post-translational modifications near the quinone binding site of mammalian complex I.  J. Biol. Chem. 288, 24799–08.

Glycoprotein analysis

  1. Siguier, B. et al. (2014) First structural insights into α-L-Arabinofuranosidases from the two GH62 Glycoside hydrolase subfamilies. J. Biol. Chem. 289, 5261–73.
  2. Vakhrushev, S. et al. (2013) Enhanced mass spectrometric mapping of the human GalNAc-type O-glycoproteome with SimpleCells. Mol. Cell. Prot. 12, 932–44.
  3. Berk, J. et al. (2013) . O-Linked β-N- Acetylglucosamine (O-GlcNAc) Regulates emerin binding to autointegration Factor (BAF) in a chromatin and Lamin B-enriched “Niche”.  J. Biol. Chem. 288, 30192–09.

Phosphoprotein analysis

  1. Roux, P. and Thibault, P. (2013) The Coming of Age of phosphoproteomics –from Large Data sets to Inference of protein Functions. Mol. Cell. Prot. 12, 3453–64.

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Explore our portfolio of proteases today.