Description

m-dPEG®48-MAL, product number QBD-10932, is a sulfhydryl-reactive, single molecular weight, with a long (152 atoms, 178.6 Å), discrete-chain-length PEG (dPEG®). This product modifies surfaces and biomolecules with free thiol groups through the maleimide reactive group. The non-immunogenic, methyl-terminated dPEG® chain has no charge but adds water solubility and hydrodynamic volume to molecules to which it is conjugated.

The reaction of the maleimide end of m-dPEG®48-MAL, product number QBD-10932, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which creates confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.

Possible uses for m-dPEG®48-MAL include the following:
Surface coating and passivation of thiolated nanoparticles;
Modification of cysteine residues on peptides, proteins, and other sulfhydryl-containing molecules to increase hydrophilicity and decrease immunogenicity;
Modification of cysteine residues on peptides, proteins, and other sulfhydryl-containing molecules to increase hydrodynamic volume and reduce or eliminate renal clearance of the modified compound;
Supramolecular construction (for example, of hydrogels); and,
As a probe of protein structure or enzymatic function.

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.

Complement Activation and Cell Uptake Responses Toward Polymer-Functionalized Protein Nanocapsules. Nicholas M. Molino, Kateryna Bilotkach, Deborah A. Fraser, Dongmei Ren, and Szu-Wen Wang. Biomacromolecules, 2012, 13 (4), pp 974–981. March 14, 2012. DOI: 10.1021/bm300083e.

Description

m-dPEG^®₃₆-MAL, product number QBD-10931, is a sulfhydryl-reactive, single molecular weight, with a long (116 atoms, 137.2 Å), discrete-chain-length PEG (dPEG^®). This product modifies surfaces and biomolecules with free thiol groups through the maleimide reactive group. The non-immunogenic, methyl-terminated dPEG® chain has no charge but adds water solubility and hydrodynamic volume to molecules to which it is conjugated.

The reaction of the maleimide end of m-dPEG^®₃₆-MAL, product number QBD-10931, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which creates confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.

Possible uses for m-dPEG^®₃₆-MAL include the following:
Surface coating and passivation of thiolated nanoparticles;
Modification of cysteine residues on peptides, proteins, and other sulfhydryl-containing molecules to increase hydrophilicity and decrease immunogenicity;
Modification of cysteine residues on peptides, proteins, and other sulfhydryl-containing molecules to increase hydrodynamic volume and reduce or eliminate renal clearance of the modified compound;
Supramolecular construction (for example, of hydrogels); and,
As a probe of protein structure or enzymatic function.

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). See all of the extensive references to the reactions of maleimides with a variety of compounds and applications, Hermanson, p.1174 (index for maleimides) and references therein.

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

m-dPEG®8-MAL, product number QBD-10746, is a thiol-reactive, single molecular weight, monodisperse PEG reagent with a spacer length of 32 atoms. The terminal maleimido group reacts rapidly and specifically at pH 6.5 – 7.5 with free thiols to form thioether bonds in a click chemistry type of reaction. The non-immunogenic dPEG® product increases the water solubility and hydrodynamic volume of conjugates made with it. Moreover, this product reduces or eliminates immunogenicity and non-specific interactions caused by hydrophobicity. This product is designed to modify small molecules, biomolecules, hydrogels, and surfaces (metal, glass, silica) containing free sulfhydryl groups.

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). See all of the extensive references to the reactions of maleimides with a variety of compounds and applications, Hermanson, p.1174 (index for maleimides) and references therein.

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

m-dPEG®4-MAL, product number QBD-10745, is a thiol-reactive, single molecular weight, monodisperse PEG reagent that forms thioethers with sulfhydryls. The terminal maleimido group reacts rapidly and specifically at pH 6.5 – 7.5 with free thiols in a click chemistry type of reaction. The non-immunogenic dPEG® product increases the water solubility and hydrodynamic volume of conjugates made with it. Moreover, this product reduces or eliminates immunogenicity and non-specific interactions caused by hydrophobicity. This product is designed to modify small molecules, biomolecules, hydrogels, and surfaces (metal, glass, silica) containing free sulfhydryl groups.

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). See all of the extensive references to the reactions of maleimides with a variety of compounds and applications, Hermanson, p. 1174 (index for maleimides) and references therein.

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

MAL-dPEG®4-acid, product number QBD-10338, is a short (16 atoms) crosslinker that joins sulfhydryl groups to free amines through a single molecular weight polyethylene glycol (PEG) chain of discrete length. The maleimidopropyl moiety reacts with sulfhydryl groups via a Michael addition reaction. The propionic acid terminus of the molecule reacts directly with free amines using EDC or another carbodiimide to form amide bonds. Alternatively, activation of the propionic acid group with N-hydroxysuccinimide (NHS), 2,3,5,6-tetrafluorophenol (TFP), or some other acylating agent permits amide bond formation under mild, controlled conditions.

Chemical couplings between free amines and free thiols are among the most popular, most useful crosslinking reactions in bioconjugate chemistry. These syntheses require heterobifunctional reagents that bridge the two groups. While traditional crosslinkers are hydrophobic molecules, Vector Laboratories’ crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths, hence the dPEG® tradename under which we sell them. Almost inevitably, the conjugation of conventional hydrophobic crosslinking reagents to biomolecules triggers problems such as aggregation and precipitation of the conjugates. Conversely, these problems do not occur with our water-soluble, non-immunogenic dPEG® crosslinkers.

The reaction of the maleimide end of MAL-dPEG®4-acid with a sulfhydryl proceeds optimally at pH 6.5 – 7.5. Use the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.

After the maleimide end of the molecule reacts with a sulfhydryl, the terminal propionic acid group may be left unreacted for charge modification or the conjugate or activated with an acylating agent such as NHS or TFP. The active ester then reacts with free amines to complete the crosslink.

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); See pp. 276-335 for general description and use of heterobifunctional crosslinkers, and the specific sample protocol for SMCC or sulfo-SMCC on pp. 283-286.

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

MPS-Acid, product number QBD-10323, is 3-maleimidopropanoic acid, a thiol-reactive crosslinker for linking sulfhydryl groups with free amines. Although it is not a dPEG® product, MPS-Acid is a building block for Vector Laboratories’ complete line of Maleimide-dPEG®x products. As a crosslinker, the spacer is from the reactive site of the maleimide to the carbonyl carbon of the propanoic acid.

The maleimido group reacts with sulfhydryl groups to form thiol ether bonds. In the range of pH 6.5 – 7.5, the thiol-maleimide reaction is chemoselective. Above pH 7.5, the maleimide group can also react with free amine groups. Consequently, high pH buffers should be avoided when using this product.

This product can be functionalized with an active ester such as N-hydroxysuccinimide (NHS); 2,3,5,6-tetrafluorophenol (TFP); or 2,3,4,5,6-pentafluorophenol (PFP) in order to react with free amines. Alternatively, the acid moiety can be coupled directly to free amines using a water-soluble carbodiimide such as 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC).

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

m-dPEG®24-MAL, product number QBD-10319, is a sulfhydryl-reactive, single molecular weight, with a discrete chain length PEG (dPEG®). This product modifies surfaces and biomolecules with free thiol groups through the maleimide reactive group. The non-immunogenic, methyl-terminated dPEG® chain has no charge but adds water solubility and hydrodynamic volume to molecules to which it is conjugated.

The reaction of the maleimide end of m-dPEG®24-MAL, product number QBD-10319, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which creates confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.
Published uses for m-dPEG®24-MAL include the following:
modifying surface-accessible free thiols on enzymes to probe enzymatic function;
developing a virus-based drug delivery system; and,
developing probes of cellular redox reactions.

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.

Modulation of Cell Surface Protein Free Thiols: A Potential Novel Mechanism of Action of the Sesquiterpene Lactone Parthenolide. Jolanta Skalska, Paul S. Brookes, Sergiy M. Nadtochiy, Shannon P. Hilchey, Craig T. Jordan, Monica L. Guzman, Sanjay B. Maggirwar, Margaret M. Briehl, Steven H. Bernstein. PLoS ONE. 4 (12), e8115. December 2, 2009. DOI: 10.1371 /journal.pone.0008115.

Cell-Specific Delivery of Diverse Cargos by BacteriophageMS2 Virus-like Particles. Carlee E. Ashley Eric C. Carnes, Genevieve K. Phillips, Paul N. Durfee, Mekensey D. Buley, Christopher A. Lino, David P. Padilla, Brandy Phillips, Mark B. Carter, Cheryl L. Willman, C. Jeffrey Brinker, Jerri do Carmo Caldeira, Bryce Chackerian, Walker Wharton, and David S. Peabody.ACS Nano, 2011, 5 (7), pp 5729–5745, May 26, 2011. DOI: 10.1021/nn201397z.

Going through the barrier: coupled disulfide exchange reactions promote efficient catalysis in Quiescin sulfhydryl oxidase. Benjamin A. Israel, Vamsi K. Kodali, and Colin Thorpe. The Journal of Biological Chemistry. 2013, December 30, 2013. DOI: 10.1074/jbc.M113.536219.

2-Cys peroxiredoxins participate in the oxidation of chloroplast enzymes in the dark. Valle Ojeda, Juan Manuel, Pérez-Ruiz, and Francisco Javier Cejudo. Molecular Plant. 2018, pp 1-32. October 4, 2018. DOI: 10.1016/j.molp.2018.09.005.

Complement Activation and Cell Uptake Responses Toward Polymer-Functionalized Protein Nanocapsules. Nicholas M. Molino, Kateryna Bilotkach, Deborah A. Fraser, Dongmei Ren, and Szu-Wen Wang. Biomacromolecules, 2012, 13 (4), pp 974–981. March 14, 2012. DOI: 10.1021/bm300083e.

Redox-regulated dynamic interplay between Cox19 and the copper-binding protein Cox11 in the intermembrane space of mitochondria facilitates biogenesis of cytochrome c oxidase. Manuela Bode, Michael W. Woellhaf, Maria Bohnert, Martin van der Laan, Frederik Sommer, Martin Jung, Richard Zimmermann, Michael Schroda, Johannes M. Herrmann. Molecular Biology of the Cell. April 29, 2015. DOI: 10.1091/mbc.E14-11-1526

NTRC-dependent redox balance of 2-Cys peroxiredoxins is needed for optimal function of the photosynthetic apparatus. Juan Manuel Pérez-Ruiz, Belén Naranjo, Valle Ojeda, Manuel Guinea, and Francisco Javier Cejudo. Proceedings of the National Academy of Sciences of the United States of America. 2017, 114 (45) pp 12069-12074. 9/26/2017. DOI: 10.1073/pnas.1706003114.

A chloroplast redox relay adapts plastid metabolism to light and affects cytosolic protein quality control. Valle Ojeda, Julia Jiménez-López, Francisco José Romero-Campero, Francisco Javier Cejudo, Juan Manuel Pérez-Ruiz. Plant Physiology. 2021, kiab246. 05/26/2021. DOI: 10.1093/plphys/kiab246

Protocol for determining protein cysteine thiol redox status using western blot analysis, Bikram Datt Pant, Sunhee Oh, Hee-Kyung Lee, Raja Sekhar Nandety, Kirankumar S. Mysore, Volume 33, Issue 11, 15 December 2020, https://doi.org/10.1016/j.xpro.2021.100566

Aim32 is a dual-localized 2Fe-2S mitochondrial protein that functions in redox quality control, Danyun Zhang, Owen R. Dailey, Daniel J. Simon, James A. Wohlschlegel, Carla M. Koehler, Deepa V. Dabir, Journal of Biological Chemistry, 2021, Volume 297, Issue 4, 10/2021, DOI: 10.1016/j.jbc.2021.101135

Depletion of m-type thioredoxin impairs photosynthesis, carbon fixation, and oxidative stress in cyanobacteria. Manuel J Mallén-Ponce, María José Huertas, Ana María Sánchez-Riego, Francisco J Florencio. Plant Physiology. 2021. Volume 187, Issue 3. July 15, 2021. DOI: 10.1093/plphys/kiab321

Characterization of the Gluathione-dependent reduction of the perixiredoxin 5 homolog PfAOP from Plasmodium Falciparum. Robin Chumann, Lukas Lang, Marcel Deponte. Wiley Online Library. 2022. Volume 31, Issue 5. April 9, 2022. https://doi.org/10.1002/pro.4290

Regulation of Derlin-1-mediated degradation of NADPH oxidase partner p22phox by thiol modification. Kei Miyano, Shuichiro Okamoto, Mizuho Kajikawa, Takuya Kiyohara, Chikage Kawai, Akira Yamauchi, Futoshi Kuribayashi. Redox Biology, Volume 56, October 2022, 102479. 08/12/2022. https://doi.org/10.1016/j.redox.2022.102479

Description

MAL-dPEG®24-acid, product number QBD-10315, is a crosslinker that joins sulfhydryl groups to free amines through a single molecular weight polyethylene glycol (PEG) chain of discrete length. The maleimidopropyl moiety reacts with sulfhydryl groups via a Michael addition reaction. The propionic acid terminus of the molecule reacts directly with free amines using EDC or another carbodiimide to form amide bonds. Alternatively, activation of the propionic acid group with N-hydroxysuccinimide (NHS), 2,3,5,6-tetrafluorophenol (TFP), or some other acylating agent permits amide bond formation under mild, controlled conditions.

Chemical couplings between free amines and free thiols are among the most popular, most useful crosslinking reactions in bioconjugate chemistry. These syntheses require heterobifunctional reagents that bridge the two groups. While traditional crosslinkers are hydrophobic molecules, Vector Laboratories’ crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths, hence the dPEG® tradename under which we sell them. Almost inevitably, the conjugation of conventional hydrophobic crosslinking reagents to biomolecules triggers problems such as aggregation and precipitation of the conjugates. Conversely, these problems do not occur with our water-soluble, non-immunogenic dPEG® crosslinkers.

The reaction of the maleimide end of MAL-dPEG®24-acid with a sulfhydryl proceeds optimally at pH 6.5 – 7.5. Use the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.

After the maleimide end of the molecule reacts with a sulfhydryl, the terminal propionic acid group may be left unreacted for charge modification or the conjugate or activated with an acylating agent such as NHS or TFP. The active ester then reacts with free amines to complete the crosslink.

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); See pp. 276-335 for general description and use of heterobifunctional crosslinkers, and the specific sample protocol for SMCC or sulfo-SMCC on pp. 283-286.

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

m-dPEG®12-MAL, product number QBD-10289, is a sulfhydryl-reactive, single molecular weight, with a discrete chain length PEG (dPEG®). This product modifies surfaces and biomolecules with free thiol groups through the maleimide reactive group. The non-immunogenic, methyl-terminated dPEG® chain has no charge but adds water solubility and hydrodynamic volume to molecules to which it is conjugated.

The reaction of the maleimide end of m-dPEG®12-MAL, product number QBD-10289, with a sulfhydryl proceeds best at pH 6.5 – 7.5. Conduct the conjugation at the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which creates confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.

Published uses for m-dPEG®12-MAL include probing the molecular structure and function of proteins and coating nanoparticle surfaces. In particular, studies of molecular structure and function of proteins would not be possible with traditional, dispersed PEG products because the dispersed PEGs would have created an indecipherable mixture of conjugation products. Only a dPEG® product could work in this application.

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). See all of the extensive references to the reactions of maleimides with a variety of compounds and applications, Hermanson, p.1174 (index for maleimides) and references therein.

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.

Homodimerisation of the Lymph Vessel Endothelial Receptor LYVE-1 through a Redox-Labile Disulfide is Critical for Hyaluronan Binding in Lymphatic Endothelium. Suneale Banerji, William Lawrance, Clive Metcalfe, David C. Briggs, Akira Yamauchi, Omer Dushek, P. Anton van der Merwe, Anthony J. Day, and David G. Jackson. The Journal of Biological Chemistry. 2016, October 12, 2016. DOI: 10.1074/jbc.M116.736926.

Interleukin-2 signalling is modulated by a labile disulfide bond in the CD132 chain of its receptor. Clive Metcalfe, Peter Cresswell and A. Neil Barclay. Open Biology. 2012, 2 (1). January 11, 2012. DOI: 10.1098/rsob.110036.

DksA2, a zinc-independent structural analog of the transcription factor DksA. Ran Furman, Tapan Biswas, Eric M. Danhart, Mark P. Foster, Oleg V. Tsodikov, Irina Artsimovitch. FEBS Letters. 2013, 587 (6) pp 614–619. January 31, 2013. DOI: 10.1016/j.febslet.2013.01.073.

Rapid ratiometric biomarker detection with topically applied SERS nanoparticles. Yu “Winston” Wang, Altaz Khan, Madhura Som, Danni Wang, Ye Chen, Steven Y. Leigh, Daphne Meza, Patrick Z. McVeigh, Brian C. Wilson and Jonathan T.C. Liu. Technology. 2014, 2 (2) pp 1-15. May 19, 2014. DOI: 10.1142/S2339547814500125.

Redox-regulated dynamic interplay between Cox19 and the copper-binding protein Cox11 in the intermembrane space of mitochondria facilitates biogenesis of cytochrome c oxidase. Manuela Bode, Michael W. Woellhaf, Maria Bohnert, Martin van der Laan, Frederik Sommer, Martin Jung, Richard Zimmermann, Michael Schroda, Johannes M. Herrmann. Molecular Biology of the Cell. April 29, 2015. DOI: 10.1091/mbc.E14-11-1526

A glutaredoxin in the mitochondrial intermembrane space has stage-specific functions in the thermo-tolerance and proliferation of African trypanosomes. Samantha Ebersoll, Blessing Musunda, Torsten Schmenger, Natalie Dirdjaja, Marian Bonilla, Bruno Manta, Kathrin Ulrich, Marcelo A. Comini, and R. Luise Krauth-Siegel. Redox Biology. 2018, 15, pp 532-547. January 31, 2018. DOI: 10.1016/j.redox.2018.01.011.

Description

MAL-dPEG®12-acid, product number QBD-10285, is a crosslinker that joins sulfhydryl groups to free amines through a single molecular weight polyethylene glycol (PEG) chain of discrete length. The maleimidopropyl moiety reacts with sulfhydryl groups via a Michael addition reaction. The propionic acid terminus of the molecule reacts directly with free amines using EDC or another carbodiimide to form amide bonds. Alternatively, activation of the propionic acid group with N-hydroxysuccinimide (NHS), 2,3,5,6-tetrafluorophenol (TFP), or some other acylating agent permits amide bond formation under mild, controlled conditions.

Chemical couplings between free amines and free thiols are among the most popular, most useful crosslinking reactions in bioconjugate chemistry. These syntheses require heterobifunctional reagents that bridge the two groups. While traditional crosslinkers are hydrophobic molecules, Vector Laboratories’ crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths, hence the dPEG® tradename under which we sell them. Almost inevitably, the conjugation of conventional hydrophobic crosslinking reagents to biomolecules triggers problems such as aggregation and precipitation of the conjugates. Conversely, these problems do not occur with our water-soluble, non-immunogenic dPEG® crosslinkers.

The reaction of the maleimide end of MAL-dPEG®12-acid with a sulfhydryl proceeds optimally at pH 6.5 – 7.5. Use the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid.

After the maleimide end of the molecule reacts with a sulfhydryl, the terminal propionic acid group may be left unreacted for charge modification or the conjugate or activated with an acylating agent such as NHS or TFP. The active ester then reacts with free amines to complete the crosslink.

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); See pp. 276-335 for general description and use of heterobifunctional crosslinkers, and the specific sample protocol for SMCC or sulfo-SMCC on pp. 283-286.

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.

Synthesis and anti-HIV activity of trivalent CD4-mimetic miniproteins. Hengguang Li, Yongjun Guan, Agnieszka Szczepanska, Antonio J. Moreno-Vargas, Ana T. Carmona, Inmaculada Robina, George K. Lewis and Lai-Xi Wang. Bioorganic & Medicinal Chemistry. 2007, 15 (12) pp 4220–4228. June 15, 2007. doi.org/10.1016/j.bmc.2007.03.064.