Custom Protein-Small Molecule Conjugation Service

Protein-small molecule conjugation is the most widely used method for antibody discovery against small antigens. With years of experience, our scientists at Creative Biolabs have developed a series of labeling methods to meet the specific needs of each customer.

Protein-Small Molecule Conjugation Services

The conjugation of small molecules (SM) to proteins is essential in a variety of biological areas, especially the polyclonal/monoclonal antibody production against small antigens. Because of the small size, many molecules fail to elicit an immune response and must be coupled to carrier proteins, such as bovine serum albumin (BSA) and keyhole limpet hemocyanin (KLH). In general, small molecule carboxyl, hydroxyl, and amine residues will couple to amine and sulfhydryl residues on proteins. What's more, in enzyme-linked immunosorbent assay (ELISA), the protein-small molecule conjugates can also be used to coat the ELISA plate. Creative Biolabs provides novel protein-small molecule conjugation services for our customers all over the world.

Cytotoxic Payload

Cytotoxic payload is a crucial part of the design of antibody-drug conjugates (ADCs). In broad terms, the cytotoxic payload can be divided into cellular toxins, protein toxins, and radionuclides. Different cytotoxic payloads always present unique mechanisms of action against target cells, there are three categories including tubulin ﬁlaments damaging, DNA damaging, and transcription inhibition. To trigger cytotoxic effects, the payload must have extremely high cytotoxic potency molecules and be small in structure to reduce the risk of immunogenicity.

Biotin

Biotin, also known as vitamin B7, belongs to the B vitamins that are involved in a wide range of metabolic processes. In biological research, biotin is often used with conjugated avidin in two-step detection systems. Biotinylation is the process of coupling biotin to proteins and other macromolecules. N-Hydroxysuccinimide (NHS)-activated biotin is the most common biotinylation reagent.

Digoxin

Digoxin, also known as Digitalis, is a medication for the treatment of various heart conditions. Digoxin is one of the classical medications in the field of cardiology that belongs to the cardiac glycoside family of medications. To develop diagnostic antibodies against digoxin, the digoxin derivative/immunogenic protein conjugate would be used as an antigen.

Protein-Small Molecule Conjugates Method

Small molecules with carboxyl, hydroxyl, and amine residues can be coupled to proteins according to linkage techniques. Carboxylic acid groups are often coupled with protein amine groups to form stable conjugates through amide bonds. Although carbodiimides are always unstable, most small molecules and carbodiimides are soluble in dry organic solvents. What's more, the addition of NHS to small molecules prior to the addition of carbodiimide generates activated NHS esters that can further enhance the stability of the system. Small molecules containing carboxylic acid residues can be coupled to proteins by simply reversing the carbodiimide reaction. Moreover, a variety of cleavable linkers and non-cleavable linkers are all available.

Fig. 1 Structural elucidation of antibody- drug conjugates (ADCs) using the IgG crystal structure.¹

Creative Biolabs offers the most advanced and comprehensive protein-small molecule conjugation services. We work to amplify your success in a highly collaborative manner. If you are interested in our services, please do not hesitate to contact us for detailed information.

Reference

Feng, Y. et al. Conjugates of small molecule drugs with antibodies and other proteins. Biomedicines. 2014, 2(1): 1-13.
under Open Access license CC BY 3.0, without modification.