What is a ubiquitinated peptide?
A ubiquitinated peptide contains a defined ubiquitin-derived modification attached to a specific peptide site. Depending on the project, this may mean a full ubiquitin conjugate, a linkage-defined construct, or a Lys(GG) peptide representing the tryptic ubiquitination remnant.
How are ubiquitinated peptides synthesized?
Routes may combine Fmoc-based solid-phase peptide synthesis, orthogonal lysine protection, segment ligation, isopeptide-bond formation, chemoselective conjugation, preparative purification, and analytical characterization.
What is a Lys(GG) peptide?
A Lys(GG) peptide contains diglycine attached to the lysine ε-amino group. It models the remnant commonly retained after tryptic digestion of a ubiquitinated protein and is widely used in ubiquitin proteomics.
Is a Lys(GG) peptide the same as a full ubiquitinated peptide?
No. Lys(GG) is a small proteomic remnant standard, whereas a full ubiquitinated peptide carries ubiquitin or a larger ubiquitin-derived construct. Their size, structure, synthesis, and applications are different.
Can you prepare native isopeptide linkages?
Native or near-native linkage strategies may be possible depending on the sequence, construct size, attachment site, topology, and scale. Each project requires a feasibility review.
Which ubiquitin linkage types can be designed?
Projects may involve K6, K11, K27, K29, K33, K48, K63, M1, mixed, or branched architectures. Availability depends on the requested construct and synthetic feasibility.
Can ubiquitinated peptides contain stable isotope labels?
Yes. Heavy amino acids can be incorporated into Lys(GG) and other ubiquitin-related peptide standards for targeted quantitative LC-MS applications.
Can ubiquitination be combined with other PTMs?
Selected combinations with phosphorylation, acetylation, methylation, citrullination, glycosylation, labels, affinity tags, or click handles may be possible when the full synthetic route is compatible.
How are ubiquitinated peptides characterized?
Typical testing may include analytical HPLC and mass spectrometry. High-resolution MS, MS/MS mapping, amino acid analysis, or other project-specific methods can be considered when appropriate.
What information is needed for a quotation?
Provide the target sequence, residue numbering, modified lysine, desired ubiquitin format or linkage, quantity, purity, formulation, additional modifications, and intended application.