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SILuLite SigmaMAb Universal Antibody Standard human

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IgG1 light, Mass Spectrometry Universal Antibody Standard, SILuLite SigmaMAb Universal Antibody Standard human, recombinant IgG1 lambda light antibody, SigmaMAb


expressed in CHO cells

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wet ice

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storage temp.


storage temp.


storage temp.


storage temp.



expressed in CHO cells


expressed in CHO cells


expressed in CHO cells


expressed in CHO cells

Quality Level


Quality Level


Quality Level


Quality Level


General description

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

Physical form

Supplied as a lyophilized powder containing phosphate buffered saline

Preparation Note

SigmaMAb recovery is maximized when phosphate buffer, pH 6–7, is used to reconstitute the lyophilized product.

Analysis Note

SigmaMab Heavy Chain

SigmaMab Light Chain
Also available as a stable isotope-labled product, SiluMab (Product Number MSQC3)
Package size based on protein content determined by A280

Other Notes

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.

Legal Information

SILu is a trademark of Sigma-Aldrich Co. LLC

Storage Class

11 - Combustible Solids




Not applicable


Not applicable

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Jared B Shaw et al.
Analytical chemistry, 90(18), 10819-10827 (2018-08-18)
Compared to traditional collision induced dissociation methods, electron capture dissociation (ECD) provides more comprehensive characterization of large peptides and proteins as well as preserves labile post-translational modifications. However, ECD experiments are generally restricted to the high magnetic fields of FTICR-MS
Daniel A Polasky et al.
Analytical chemistry, 91(4), 3147-3155 (2019-01-23)
Ion mobility-mass spectrometry (IM-MS) has become an important addition to the structural biology toolbox, but separating closely related protein conformations remain challenging. Collision-induced unfolding (CIU) has emerged as a valuable technique for distinguishing iso-cross-sectional protein and protein complex ions through
John P McGee et al.
Journal of the American Society for Mass Spectrometry, 31(3), 763-767 (2020-03-05)
Intact protein mass spectrometry (MS) via electrospray-based methods is often degraded by low-mass contaminants, which can suppress the spectral quality of the analyte of interest via space-charge effects. Consequently, selective removal of contaminants by their mobilities would benefit native MS
Yutong Jin et al.
mAbs, 11(1), 106-115 (2018-09-20)
The pharmaceutical industry's interest in monoclonal antibodies (mAbs) and their derivatives has spurred rapid growth in the commercial and clinical pipeline of these effective therapeutics. The complex micro-heterogeneity of mAbs requires in-depth structural characterization for critical quality attribute assessment and
Anna C Robotham et al.
mAbs, 11(4), 757-766 (2019-03-22)
The detection of free sulfhydryls in proteins can reveal incomplete disulfide bond formation, indicate cysteine residues available for conjugation, and offer insights into protein stability and structure. Traditional spectroscopic methods of free sulfhydryl detection, such as Ellman's reagent, generally require


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