Native Lys-N, Mass Spec Grade

• Cat.No.: Lys-N-40

Specification

• Description: Lys-N is an innovative protease that specifically hydrolyzes peptide bonds at the N-terminal of lysine residues. This enzyme can be applied for post-translational modification (PTM) protein research, and it produces more b ions than y ions in the spectrometer. Combing the use of Lys-N with rTrypsin-N gives the best way for protein sequencing.
• Form: Lyophilized powder
• Bio-activity: 394 U/mg
• Molecular Mass: 18.4 kDa
• Purity: > 99.5 % peak area analyzed by HPLC at 280 nm.
• Storage: Store the lyophilized powder at -20 centigrade. Store reconstituted enzyme at -80 centigrade for up to 30 days.
• EC No.: EC 3.4.24.20
• Shelf life: 24 months at -80 centigrade.
• Stability: Maximally active in the pH range 7-9.
• Usage Notes: In-Solution Protein Digestion Protocol: 1. Resuspend 20 μg of Mass Spectrum Grade Lys-N in 40 μL resuspension buffer for maximum activity. 2. Add 50 mM ammonium bicarbonate or Tris-HCl (pH 8) to protein mixture (recommended). 3. Add 0.5 μg/μL Lys-N to reach a final enzyme to substrate ratio of 1: 30 to digest the samples. Mix well and incubate at 37 centigrade for 4 hours.
• Specificity: < 5 % nonspecific cleavage with Eschericha Coli digests (digestion at 37 centigrade for 4 hours), analyzed by LCMS/MS.
• Unit Definition: 1 unit of proteolytic activity towards azocasein is defined as the amount of enzyme required for half-maximal OD366 after a 30 min incubation at 37 centigrade, pH 10, A366, and light path=1cm.
• LC-MS/MS Analysis: Human serum albumin (HSA) was dissolved, denatured at 37 centigrade for 1 h, diluted at pH 8.0, and incubated with Lys-N for 4 hours. The digest was analyzed by LC-MS/MS. Experimental peptide results match the peptides generated in a theoretical digest of HSA by Lys-N.
• Resuspension Buffer: 50 μM Zinc Acetic buffer or Zinc Sulfate buffer.
• MALDI-TOF Analysis: No impurity peak found of Lys-N, analyzed by MALDI-TOF