MAL-dPEG®₂₄-Tris(-dPEG®₂₄-Tris (m-dPEG®₂₄)₃)₃ (QBD-11487)

Description

MAL-dPEG®24-Tris(-dPEG®24-Tris (m-dPEG®24)3)3, product number QBD-11487, is a nine-branched, 15.4 kDa, sulfhydryl-reactive, monodispersed PEGylation reagent built around tris cores from high-purity, single molecular weight, discrete PEG (dPEG®) compounds. The attachment point is a thiol-reactive maleimide group. Nine uncharged methoxy-terminated dPEG®24 linkers arising from four tris cores in a 1:3 arrangement form the branches. The average dPEG® spacer length from the maleimide ring attachment point to the terminal methoxy groups is 247 atoms (158.8 Å). This product is designed for biomolecular conjugation to modulate the pharmacokinetics (PK) and biodistribution (BD) of biomolecules such as antibodies or other proteins. It may also be used to passivate surfaces to prevent non-specific interactions.

Vector Laboratories’ dPEG® technology uses high-purity, single molecular-weight PEG linkers and spacers with discrete chain lengths. In contrast, traditional, non-uniform polymer PEG linkers and spacers have an intractable mixture of different chain lengths of PEG, where each length of PEG in the mix has a unique molecular weight. Analyzing dPEG® products and conjugates made with them is far more straightforward than analyzing non-uniform PEG products and their conjugates.

The terminal maleimide group in MAL-dPEG®24-Tris(-dPEG®24-Tris(m-dPEG®24)3)3, product number QBD-11487, provides the sole attachment point for the dPEG® construct to join a free thiol (sulfhydryl) group, forming a stable thioether bond. Surface-accessible, free thiols are uncommon in biomolecules but may be preferred over surface-accessible amines for PEGylation of biomolecules. Free thiols can also be exposed by creating antibody fragments or reduction reactions targeting disulfide bonds.

PEGylation of biomolecules with MAL-dPEG®24-Tris(-dPEG®24-Tris(m-dPEG®24)3)3 greatly increases a conjugate molecule’s hydrodynamic volume and water solubility and shields the conjugate from opsonization by the immune system. These effects prevent renal clearance of the conjugate by the body and reduce or eliminate opsonization, extending the conjugate’s serum half-life. The longer serum half-life can lead to lower dosing requirements for the PEGylated conjugate compared to the non-PEGylated conjugate while maintaining diagnostic or therapeutic efficacy.

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References

Greg T. Hermanson, Bioconjugate Techniques, 3rd Edition, Elsevier, Waltham, MA 02451, 2013, ISBN 978-0-12-382239-0; See Chapter 18, Discrete PEG Reagents, pp. 787-821, for a full overview of the dPEG® products.