Description

DBCO-dPEG®12-TFP ester, product number QBD-11366, is a heterobifunctional, bioorthogonal crosslinker designed to join azides and amines across a medium-length (40 atoms, 46.3 Å), flexible, hydrophilic, single molecular weight, discrete PEG (dPEG®) spacer. The tetrafluorophenyl (TFP) ester reacts specifically with free amines to form amide bonds; the optimum reaction pH is 7.5 – 8.0. The dibenzylcyclooctyne (DBCO) moiety selectively forms triazole linkages with azides via a click chemistry reaction known as strain-promoted azide-alkyne cycloaddition (SPAAC), also known as copper-free click chemistry. The amphiphilic dPEG® linker increases conjugates’ hydrodynamic volumes, and it can be used to create space in sterically crowded supramolecular constructs.

Specifications

Documents

References

Greg T. Hermanson, Bioconjugate Techniques, 2nd Edition, Elsevier Inc., Burlington, MA 01803, April, 2008 (ISBN-13: 978-0-12-370501-3; ISBN-10: 0-12-370501-0). Specifically see pp. 726-729 in his Chapter 18 on discrete PEG compounds for pegylation applications.

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.

Description

Hydroxy-dPEG®12-TFP ester, product number QBD-11345, is a medium-length (40 atoms, 46.2 Å), hydroxy-terminated, single molecular weight, discrete polyethylene glycol (dPEG®) compound functionalized with a 2,3,5,6-tetrafluorophenyl (TFP) ester for conjugation to primary and secondary amines. This product can be used for modification of amine-functionalized surfaces (e.g., silica, glass), modification of proteins and peptides at accessible amine sites on the molecules, the construction of discrete PEG dendrimers, and many other applications. The free hydroxy end of the dPEG® spacer can be functionalized for further reactions or left unmodified to increase hydrophilicity or modify the charge of conjugate molecules and surfaces.

Specifications

Documents

References

Greg T. Hermanson, Bioconjugate Techniques, 2nd Edition, Elsevier Inc., Burlington, MA 01803, April, 2008 (ISBN-13: 978-0-12-370501-3; ISBN-10: 0-12-370501-0). Specifically see pp. 726-729 in his Chapter 18 on discrete PEG compounds for pegylation applications.

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.

Description

Bromoacetamido-dPEG®12-amido-DBCO, product number QBD-11223, combines a thiol-reactive bromoacetyl group with dibenzylcyclooctyne (DBCO, also known as DIBAC), a copper-free click chemistry reactive group. The two reactive groups link via a medium-length (40 atoms, 46.1 Å), flexible, single molecular weight, discrete polyethylene glycol (dPEG®) linker. The bromoacetyl group reacts chemoselectively with thiols at pH ≥ 8.0. This differs from the maleimide group, which reacts chemoselectively with sulfhydryls within the range of pH 6.5 – 7.5. The DBCO moiety is a strained cyclooctyne ring flanked by two benzyl rings on either side. DBCO was designed for strain promoted azide-alkyne cycloaddition (SPAAC), also known as copper-free click chemistry.

Specifications

Documents

References

Greg T. Hermanson, Bioconjugate Techniques, 2nd Edition, Elsevier Inc., Burlington, MA 01803, April, 2008 (ISBN-13: 978-0-12-370501-3; ISBN-10: 0-12-370501-0). Specifically see pp. 726-729 in his Chapter 18 on discrete PEG compounds for pegylation applications.

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.

Description

Bromoacetamido-dPEG®12-TFP ester, product number QBD-11202, is a medium-length (42 atoms, 48.7 Å), single molecular weight, discrete PEG (dPEG®) crosslinker functionalized with a thiol-reactive bromoacetate group on one end and an amine-reactive 2,3,5,6-tetrafluorophenyl (TFP) ester on the other.

The medium-length, flexible, non-immunogenic dPEG® crosslinker increases the hydrodynamic volumes of conjugates in aqueous media, thereby increasing water solubility. The increased hydrodynamic volume can reduce or eliminate conjugate molecules’ renal clearance and shield conjugates from opsonization.

The bromoacetate moiety is an alternative to the maleimide group, reacting chemoselectively with free thiols at pH ≥8.0. It is useful for situations where the conjugate molecule needs to be kept at a high pH (≥8.0), above the range where maleimides can be used effectively, or in constructs where maleimide groups are unstable.

TFP esters are an alternate reactive group to the N-hydroxysuccinimidyl (NHS) ester and reacts with amines at an optimal pH range of 7.5 – 8.0, higher than the optimal range for NHS esters (pH 7.0 – 7.5). TFP esters are more hydrolytically stable than NHS esters, and they are more reactive toward amines in their optimal pH range than NHS esters are within the pH range 7.0 – 7.5.

Specifications

Documents

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.

Description

Phthalimidooxy-dPEG®12-NHS ester, product number QBD-10011, is a protected aminooxy compound linked to an amine-reactive N-hydroxysuccinimidyl (NHS) ester through a medium-length (41 atoms, 46.3 Å), single molecular weight, discrete polyethylene glycol (dPEG®) spacer. This allows a hydrophilic, protected aminooxy group to be installed on peptides, proteins, small molecules, and amine-functionalized surfaces.

The phthaloyl moiety on phthalimidooxy-dPEG®4-NHS ester stably protects the aminooxy group. Following amide bond formation, the phthalimide group can be removed using aqueous hydrazine or hydroxylamine, leaving the aminooxy group free to react. Oxime bonds form from the reaction between an aminooxy group and an aldehyde (creating an aldoxime bond) or ketone (creating a ketoxime bond). Compared to hydrazone bonds, oxime bonds are exceptionally stable. They do not break under physiological or even slightly acidic conditions that can occur under some physiological states.

The amine-reactive NHS ester has optimal reactivity in the pH range of 7.0 – 7.4. This group should be reacted first as the subsequent deprotection step for the aminooxy group will also react with the NHS ester.

Specifications

Documents

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.

Description

Fmoc-N-amido-dPEG®12-TFP ester, product number QBD-11006 contains an Fmoc-protected amine on one end of a medium-length (40 atoms), single molecular weight, discrete-chain-length polyethylene glycol (dPEG®) spacer and the tetrafluorophenyl (TFP) ester of a propionic acid group on the other end. This product is ready for the direct introduction of a water-soluble, amphiphilic spacer into a peptide chain. The Fmoc protecting group on the N-terminus of the molecule cleaves easily with standard peptide chemistry.

Fmoc-N-amido-dPEG®12-TFP ester permits our customers to insert a dPEG® spacer into a peptide chain using standard Fmoc chemistry without the need to activate the acid terminus for conjugation. The product works equally well in solid-phase and solution-phase synthetic processes. In aqueous solutions, TFP esters are more hydrolytically stable than NHS esters and have an optimum pH range of 7.5 – 8.0 for conjugation. The dPEG® linker attaches at the N-terminal end of the peptide chain or on the free amine side chain of amino acids such as lysine. Additional peptide synthesis can be carried out to extend the peptide further, creating a peptide with a flexible, hydrophilic linker or spacer in the middle or joining two different peptides across the dPEG® bridge. In addition, the dPEG® chain can provide spacing in a synthetic construct where steric hindrance is a problem. Amphiphilic, non-immunogenic dPEG® increases the hydrodynamic volume and improves the water solubility of the conjugate while remaining soluble in organic solvents. The Fmoc protecting group is removed easily with a solution of piperidine in N,N-dimethylformamide (DMF).

Specifications

Documents

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.

Description

Fmoc-N-amido-dPEG®12-NHS ester, product number QBD-10996 contains an Fmoc-protected amine on one end of a medium-length (40 atoms), single molecular weight, discrete-chain-length polyethylene glycol (dPEG®) spacer and the N-hydroxysuccinimidyl (NHS) ester of a propionic acid group on the other end. This product is ready for the direct introduction of a water-soluble, amphiphilic spacer into a peptide chain without the need to activate the carboxylic acid moiety. The Fmoc protecting group on the N-terminus of the molecule cleaves easily with standard peptide chemistry.

Fmoc-N-amido-dPEG®12-NHS ester permits our customers to insert a dPEG® spacer into a peptide chain using solid-phase or solution-phase chemistry. The spacer attaches at the N-terminal end of the peptide chain or on the free amine side chain of amino acids such as lysine. Additional peptide synthesis can be carried out to extend the peptide further, creating a peptide with a flexible, hydrophilic linker or spacer in the middle. Also, the dPEG® compound can provide spacing in a synthetic construct where steric hindrance is a problem. Amphiphilic, non-immunogenic dPEG® increases the hydrodynamic volume and improves the water solubility of the peptide while remaining soluble in organic solvents. The Fmoc protecting group is removed easily with a solution of piperidine in N,N-dimethylformamide (DMF).

Specifications

Documents

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.

Design of a modular tetrameric scaffold for the synthesis of membrane-localized D-peptide inhibitors of HIV-1 entry. J. Nicholas Francis, Joseph S Redman, Debra M Eckert, and Michael S. Kay. Bioconjugate Chemistry, 2012, 23 (6), pp 1252-1258, May 1, 2012. DOI: 10.1021/bc300076f.

Multivalent Benzamidine Molecules for Plasmin Inhibition: Effect of Valency and Linker Length. Tanmaye Nallan Chakravarthula, Dr. Ziqian Zeng, Prof. Nathan J. Alves. ChemMedChem, Volume 17, Issue 22, (2022), 09/16/2022, https://doi.org/10.1002/cmdc.202200364.

Description

Amino-dPEG®12-t-boc hydrazide, product number QBD-10958, is a useful molecular modification and bioconjugation reagent consisting of a free, primary amine on one end of a medium-length (45 atoms, 50.1 Å) single molecular weight, discrete-chain-length polyethylene glycol (dPEG®) linker and a Boc-protected hydrazide group on the other end. The free amine reacts with carboxylic acids and their active esters to form a stable amide bond. Following the removal of the Boc protecting group, the hydrazide can be reacted with an aldehyde (for example, formed from periodate oxidation of carbohydrates) at pH 5 – 7 to form a hydrazone bond. Hydrazone bonds are acid labile but otherwise stable, thus allowing the conjugate or supramolecular construct to degrade under acidic conditions such as in lysosomes or the acidic extracellular microenvironments at inflammation or tumor metastasis sites. The single molecular weight, discrete PEG (dPEG®) crossbridge is water-soluble and non-immunogenic, and it adds flexibility and increases the hydrodynamic volume of conjugates and supramolecular constructs that incorporate it.

Specifications

Documents

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.

Description

S-acetyl-dPEG®12-OH, product number QBD-10939, contains an acetyl-protected thiol on a medium-length (36 atoms, 43.1 Å) hydroxy-terminated, discrete polyethylene glycol (dPEG®) linker. This product can be used to thiolate biomolecules.

Bioconjugation frequently employs thiolation because the reactions to install thiol groups on molecules or to react with molecules containing sulfhydryl groups are relatively simple and often chemoselective. The thioacetyl group is intended to install an acetyl-protected thiol onto biomolecules. While installing a protected thiol through a reaction between a carboxylic acid and a primary amine is widely popular in bioconjugation technology, it is not always possible or feasible. S-acetyl-dPEG®12-OH permits the installation of a protected thiol through a short, hydroxy-terminated discrete PEG® linker. Hydroxylamine hydrochloride (CAS number 5470-11-1) easily removes the S-acetyl group that protects the thiol, thus exposing the sulfhydryl for subsequent reaction. One application for S-acetyl-dPEG®12-OH is the modification of nucleic acids using phosphoramidite chemistry.

Specifications

Documents

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.

Description

dPEG®12-SATA, also known as S-acetyl-dPEG®12-NHS ester, product number QBD-10852, is one of Quanta BioDesign’s versions of the widely popular thiolation reagent N-succinimidyl-S-acetylthioacetate (SATA). The acetyl-protected thiol is separated from the N-hydroxysuccinimidyl (NHS) ester by an amphiphilic, discrete polyethylene glycol (dPEG®) spacer. The medium-length (39 atoms, 46.8 Å), flexible dPEG®12 spacer makes the product water soluble.
Thiolation is the process of adding a sulfhydryl group to a molecule. Bioconjugation frequently employs thiolation because the reactions to install thiol groups on molecules or to react molecules with sulfhydryl groups are simple and often chemoselective. The widely popular SATA reagent thiolates molecules with available amines via the NHS ester. Removal of the acetyl protecting group from the sulfhydryl permits crosslinking between the SATA-modified compound and a target molecule of interest that contains a thiol-reactive group, such as maleimide. Unfortunately, the classic SATA reagent is hydrophobic and must be dissolved in a dry, water-miscible organic solvent before use.

Vector Laboratories’ dPEG®12-SATA inserts a single molecular weight spacer between the protected thiol and the NHS ester. The dPEG® spacer imparts water solubility to the molecule, allowing dPEG®12-SATA to dissolve and react in water without the need for an organic solvent. Also, the dPEG®12 spacer adds hydrodynamic volume to the molecule to which it is conjugated, reducing aggregation and precipitation of proteins conjugated to dPEG®12-SATA. Hydroxylamine hydrochloride (CAS number 5470-11-1) easily removes the acetyl protecting group, exposing the sulfhydryl moiety for further reactions, for example, crosslinking to thiols or thiol-reactive groups like maleimides, bromoacetamides, and so forth. Any application that can be carried out with a traditional, non-PEGylated SATA reagent can be carried out with our SATA containing a dPEG® spacer.

Specifications

Documents

References

Greg T. Hermanson, Bioconjugate Techniques, 2nd Edition, Elsevier Inc., Burlington, MA 01803, April, 2008 (ISBN-13: 978-0-12-370501-3; ISBN-10: 0-12-370501-0). References to SATA which can be directly applied to the dPEG® pegylation versions: a) general description and use, p 71; b) modification of antibodies, pp 759; c)modification of amines on nucleus and DNA probes, p. 984 and d) modification of enzymes, avidin and streptavidin with pp. 90, 909 and 919.

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.

Silica-Shelled Single Quantum Dot Micelles as Imaging Probes with Dual or Multimodality. Rumiana Bakalova, Zhivko Zhelev, Ichio Aoki, Hideki Ohba, Yusuke Imai, and Iwao Kanno. Anal. Chem. 2006, 78 (16) pp 5925–5932. July 14, 2006. DOI: 10.1021/ac060412b.