SILU™ Lite SigmaMAb is a recombinant human monoclonal IgG1 lambda light antibody with a molecular mass of ∼150 kDa expressed in CHO cells. It is designed for optimization of accurate intact mass analysis of monoclonal antibodies, biosimilars, and pharmaceutical products. Accurate intact mass analysis of such large biomolecules can provide comprehensive information about structural and post-translational modifications such as glycosylation. Other information such as heterogeneity, batch-to-batch variation, amino acid truncation, and N-terminal Lys processing, aggregation, and degradation can be determined. Intact mass analysis using mass spectrometry is also very important for formulation and storage in therapeutic monoclonal antibody drug development.
It consists of two identical heavy chains and two identical light chains. The heavy chains and light chains are linked by one disulfide bond. The heavy chains are linked by two disulfide bonds located in a hinge domain. The other 12 cysteine bonds are intramolecularly restricted to six different globular domains. The antibody sequence has been evaluated by intact mass and peptide mapping using four different enzymes: chymotrypsin, Asp-N and Glu-C endoproteinases and trypsin. Sequence coverage of 100% was obtained.
SILu™ Lite SigmaMAb Universal Antibody Standard human has been used as a model system to investigate the quantitative relationship between gas-phase monoclonal antibody (mAb) unfolding and the discrete levels of mAb glycosylation.
Features and Benefits
Calculated molecular weight values of the SigmaMAb light chains, heavy chains, and intact protein, with the most abundant glycoforms, are as follows:
Description / Composition / Modification / Average Mass (Da)
Light chain, reduced / C1006H1555N267O333S7 / Pyroglutamic acid (Q) / 22942.2
Heavy chain, reduced / C2181H3393N587O663S16 / (no modification) / 48957.8
C2237H3485N591O702S16 / G0F / 50403.2
C2243H3495N591O707S16 / G1F / 50565.3
C2249H3505N591O712S16 / G2F / 50727.5
Native intact mass, non-reduced / C6374H9864N1708O1992S46 / 2 X Pyroglutamic acid (Q) / 143767.7
C6486H10048N1716O2070S46 / G0F+G0F / 146658.4
C6492H10058N1716O2075S46 / G0F+G1F / 146820.6
C6498H10068N1716O2080S46 / G1F+G1F / 146982.7
C6504H10078N1716O2085S46 / G1F+G2F / 147144.8
C6510H10088N1716O2090S46 / G2F+G2F / 147307.0
Supplied as a lyophilized powder containing phosphate buffered saline
SigmaMAb recovery is maximized when phosphate buffer, pH 6–7, is used to reconstitute the lyophilized product.
Package size based on protein content determined by A280
SigmaMab Heavy Chain
SigmaMab Light Chain
Also available as a stable isotope-labled product, Silu™Mab (Product Number MSQC3)
Avoid PBS for reconstitution.
Reconstitute the contents of the vial by adding 500μL of ultrapure water or phosphate buffer, and mixing vigorously. The solubilized product can be further diluted as needed.
SILu is a trademark of Sigma-Aldrich Co. LLC