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Advances in glycobiology highlight the role of naturally occurring glycoconjugates
in different biological processes and play a critical role in the development of
vaccines against cancer, viral and bacterial infections, and many other diseases.
The most common glycoconjugates are those where an oligosaccharide is covalently
linked to a protein, peptide or lipid, yet in some cases it can be also linked to
an oligonucleotide. Synthetic glyco-conjugates are excellent tools to elucidate
the natural glycoconjugates' roles in different biological processes. In these conjugates,
an oligosaccharide is usually cross-linked to a reporter group, such as a fluorochrome,
enzyme, liposome, colloidal gold and others, that can be easily detected. Because
of the sugars’ frequent steric requirements to recognize specific cell receptors,
e.g. selectins, these conjugates should be designed to minimize steric interference
by the newly added moiety. Bio-Synthesis has extensive experience in the commercial
synthesis of peptides and oligonucleotides coupled with its in house development
work in the area of glycosides provide the foundations for a sound approach to the
design and synthesis of these important research tools.
To obtain further information regarding custom glycoconjugation services, contact
our National Customer Services Center at 800.227.0627 or
contact us online with your detailed project descriptions. In most cases,
we can accommodate your bioconguation needs!
Bio-Synthesis may use your oligosaccharides for preparation of the conjugates or
in some cases it could prepare the whole conjugate, including the oligosaccharide
moiety. For the preparation of oligopeptides and oligonucleotides glycoconjugates
these compounds are modified during solid phase synthesis to introduce a spacer
carrying a functional group that can be used for subsequent cross-linking with the
oligosaccharides. Depending on the nature of the oligosaccharide and the peptide
or oligonucleotide, the length and hydrophilicity of the spacer would be decided
to maximize the interactions of these compounds with their receptors.
Other useful tools in biological studies are those compounds where the oligosaccharide
is coupled to a fluorescent label such as fluorescein, rhodamine, Texas red and
others, either directly or via a spacer. Fluorescent compounds can be detected by
fluorescence microscopy, FACS machine, and spectrofluorometry. Other tagging methods
involve the use of colloidal gold and ferritin, both compounds that can be detected
by electron microscopy. Oligosaccharides can also be conjugated to different lipids
to yield glycolipids that can be incorporated into either micelles or liposomes,
with the latter being effective drug carriers.
The same methods used to prepare glycoconjugates of oligosaccharides can be applied
to native polysaccharides. Based on the needs for sensitivity, nature of the molecule
recognizing the sugar moiety, Bio-Synthesis can design a method to label these macromolecules
without interfering with their interactions with other molecules.
Bio-Synthesis's custom carbohydrate bioconjugation services include experimental
design, and development of protocols and procedure for the preparation of conjugates
requested by our customers. For the last two decades, we have accumulated a portfolio
of modification and conjugation of carbohydrates to peptides, oligonucleotides,
and many other small or large molecules.
If you can't find what you want?, contact our Technical Service Center at 800.220.0627
or contact us online with your detailed project specifications,
a project manager will be assigned to help you with the design and develop an appropriate
synthetic method for your specific needs.
Biomolecules supplied by customers should be sufficiently pure. Please provide 3-5
mgs of starting material with the necessary data for purity assessment. Commercially
available biopolymers can be supplied by customers or synthesized or ordered through
Price varies based on the proejct specifications. Price does not
includes cost of small molecule or biopolymer which required to be order through
Bio-Synthesis from a commercial vendor. Some of the small molecules or biomolecules
are commerically available in an activated form. For non-active molecules, Bio-Synthesis
can assist with the design and, if deemed necessary, biopolymer modification to
introduce additional functional groups and extra linkers, spacers.
Please contact us for a quote
The custom prepared product is quality controlled
by Bio-Synthesis according to our in-house standards. These are tailored for each
individual assignment. The custom conjugate is approved only when both sets of quality
control criteria have been met.
For us to better understand your customized project, please complete our Bioconjugation Service Questionnaire. The more our chemists understand your project needs, the more accurate feedback we will be able to provide you. Provide us with your project details will enable to us to recommend the best reagents to use for your project. The most useful and readily available tools for bioconjugation projects are cross-linking reagents. A large number of cross-linkers, also known as bifunctional reagents, have been developed. There are several ways to classify the cross-linkers, such as the type of reactive group, hydrophobicity or hydrophilicity, and the length of the spacer between reactive groups. Other factors to consider are whether the two reactive groups are the same or different (for example, heterobifunctional or homobifunctional reagents), whether the spacer is cleavable, and whether the reagents are membrane permeable or impermeable. The most accessible and abundant reactive groups in proteins are the ϵ-amino groups of lysine. Therefore, a large number of the most common cross-linkers are amino selective reagents, such as imidoesters, , sulfo-N-hydroxysuccinimide esters, and N-hydroxysuccinimide esters. Due to the high reactivity of the thiol group with N-ethylmaleimide, iodoacetate and a-halocarbonyl compounds, new cross-linkers have been developed that contain maleimide and a-carbonyl moieties. Usually, N-alkylmaleimides aremore stable than their N-aryl counterparts.
In addition to the reactive groups on the cross-linkers, a wide variety of connectors and spacer arms have also been developed. The nature and length of the spacer arm play an important role in the functionality. Longer spacer arms are generally more effective when coupling large proteins or those with sterically protected reactive side-chains. Other important considerations are the hydrophobicity, hydrophilicity, and the conformational flexibility. Long aliphatic chains generally fold on themselves when in an aqueous environment, which makes the actual distance spanned by such linker arms less than expected. Instead, spacers that contain more rigid structures (for example, aromatic groups or cycloalkanes) should be used. These structures, however, tend to be very hydrophobic which could significantly decrease the solubility of the modified molecules or even modify some of their properties. In such cases, it is recommended to choose a spacer that contains an alkylether (PEO) chain. Bio-Synthesis offers several cross-linkers with PEO chains, such as thiol-binding homobifunctional reagents, heterobifunctional based, and their derivatives.
Within 3-5 days upon receiving your project scope, we will provide you an appropriate quotation. An order can be placed with PO (Purchase Order) or major credit cards ( ). Your credit card will be billed under Bio-Synthesis, Inc.