Resources

Proteomics Databases



Metabolomics Databases

• • N-Terminal Sequencing: Approaches for Confirming Mature Protein Starts and Processing Sites

  Many proteins do not begin with the first residue encoded in the gene. Signal peptides are removed during secretion. Propeptides may be cleaved before the mature form becomes active. Recombinant expression systems can leave unintended N-terminal extensions or fail to remove leader sequences as expected. In each case, the biologically relevant question is not only what the gene encodes, but where the mature protein actually starts.

• • Scoping N-Terminal Sequencing for Release Testing: Read Length, Sample Format, and Deliverables

  N-terminal sequencing projects move faster when scope is defined before samples ship. Teams often request a fixed read length without confirming whether the material supports that depth, whether the N-terminus is accessible, or whether the final report must satisfy internal QC, regulatory documentation, or publication standards. Unclear scope leads to repeated runs, extended timelines, and reports that do not match the decision the project team actually needs to make.

• • N-Terminal Sequencing Routes Compared: Edman Degradation, MS Analysis, and Peptide Mapping for QC

  N-terminal QC projects rarely fail because teams lack analytical capability. They fail because the selected route does not match the sample chemistry or the evidence standard required for the next decision. One team may need a direct ten-residue N-terminal read for lot release. Another may need to characterize a blocked recombinant terminus. A third may only need confirmation that processing removed a signal peptide correctly when a full reference sequence already exists.

• • No N-Terminal Read from Your Sample? Troubleshooting Blocked Termini and Weak Sequencing Signals

  An N-terminal sequencing project can finish without delivering the terminal answer the QC team needs. The run may complete, yet early residues are weak, ambiguous, or absent. For recombinant lot release, peptide verification, or biopharmaceutical documentation, a failed N- terminal read creates immediate delay even when intact mass and peptide mapping look acceptable.

• • Epitope Identification from PhIP-Seq Raw Data

  Learn how to identify epitope candidates from PhIP-Seq raw data through read mapping, normalization, background filtering, tiled-region analysis, and validation planning.

• • PhIP-Seq vs Traditional Phage Display for Epitope Mapping

  Compare PhIP-Seq and traditional phage display for epitope mapping by workflow, readout, library scale, epitope resolution, limitations, and validation needs.

• • Label-Free Versus Label-Based Phosphoproteomics: Selection Strategies and Comparative Advantages

  Phosphorylation is a critical post-translational modification (PTM) that plays central roles in signal transduction, cell cycle regulation, and disease development. To systematically characterize the dynamic phosphorylation landscape in cells, quantitative phosphoproteomics has emerged as an essential tool in modern life science research. Among quantitative strategies, label-based and label-free approaches represent the two principal methodologies. Overview of Quantitative Phosphoproteomics Phosphopr......

• • What Enzymes Regulate Histone Propionylation?

  Histone propionylation (HPr) is a newly recognized short-chain fatty acid-derived histone modification that plays an important role in regulating chromatin architecture and gene expression. Unlike conventional acetylation, HPr involves the addition of a propionyl group (C3 chain) to lysine residues and can serve as a more sensitive indicator of intracellular metabolic states, particularly dynamic fluctuations in propionyl-CoA. This modification has demonstrated distinct regulatory potential in hepatic......

• • What Is Histone Monoubiquitination?

  Within the nucleus, DNA does not exist as naked DNA but is tightly wrapped around histones to form chromatin structures. Histones serve not only as DNA-packaging proteins but also as critical regulators of gene expression, DNA repair, and chromosomal stability. Their functions are modulated by multiple reversible post-translational modifications (PTMs), among which monoubiquitination represents an important and distinct regulatory modification. In recent years, studies on histone monoubiquitination ha......

• • How to Detect Histone Succinylation?

  Histone succinylation (Ksucc) is a novel and important epigenetic modification that plays critical roles in chromatin remodeling, transcriptional regulation, metabolic control, and disease-associated biological processes. Owing to its low abundance and rapid dynamic changes, the detection and quantification of succinylation have become essential components of molecular biology and proteomics research. Scientific Basis of Histone Succinylation Detection 1. Chemical Characteristics Histone succinylatio......