SILu^™Lite SigmaMAb Universal Antibody Standard human

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.

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.

SigmaMab Heavy Chain
EVQLVESGGGLVQPGGSLRLSCVASGFTLNNYDMHWVRQGIGKGLEWVSKI
GTAGDRYYAGSVKGRFTISRENAKDSLYLQMNSLRVGDAAVYYCARGAGRW
APLGAFDIWGQGTMVTVSS|ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYF
PEPVTVSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVN
HKPSNTKVDKKVEPKSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISR
TPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRV
VSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPS
RDELTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFL
YSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPG

SigmaMab Light Chain
QSALTQPRSVSGSPGQSVTISCTGTSSDIGGYNFVSWYQQHPGKAPKLMIY
DATKRPSGVPDRFSGSKSGNTASLTISGLQAEDEADYYCCSYAGDYTPGV
VFGGGTKLTVL|GQPKAAPSVTLFPPSSEELQANKATLVCLISDFYPGAVTV
AWKADSSPVKAGVETTTPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQ
VTHEGSTVEKTVAPTECS

Also available as a stable isotope-labled product, Silu^™Mab (Product Number MSQC3)

Package size based on protein content determined by A₂₈₀

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