CellMosaic has a lot of experience and expertise in preparing peptide or peptidomimetic-based drug conjugates. We help our customers develop peptide labeling/conjugation strategies, synthesize the modified peptide, perform the drug conjugation, and characterize the peptide-drug conjugates. For information regarding peptide synthesis and modification at CellMosaic, please click here.

Drugs can be conjugated anywhere on the peptide (C-terminus, N-terminus, or in the middle). Usually, a single pure bioconjugate can be obtained. CellMosaic's peptide-drug conjugation process can easily be tailored to a customer's project. This is a fast approach and great solution for customers who want to develop peptide-based conjugates. Advantages of CellMosaic's peptide synthesis and conjugation strategy: 

• Freedom to attach drug or molecule of interest at any point in the peptide.
• Other functional groups, such as OH, NH₂, and SH, in the peptide will not be affected by the conjugation step.
• The conjugation strategy can easily be tweaked to couple to different categories of compounds.
• Short timeline for the development of a bioconjugation strategy.

Case Studies:

1. Developing a site-specific single-labeled peptide-polymyxin conjugate for a biotech company at CellMosaic (shown below).
• Challenge: Polymyxins are antibiotics and have a structure consisting of a cyclic peptide with a long hydrophobic tail. The cyclic peptide part contains several amino groups that are important for function. The peptide is a delivery veihicle for polymyxin and contains serveral Lys groups and Cys groups that are important for the function. To preserve the activities of both peptide and polymyxin, polymyxin should be labeled only at its hydrophobic tail site and the peptide at its C-terminus.
• Labeling strategies for polymyxin: Develop an enzymatic and chemical strategy to assemble a new antibiotic that has a single labeling site at its tail with intact head group. The strategy is applicable to other antibiotics that have a similar structure similar to polymyxin.
• Labeling strategies for peptide: Designed a single labeling site at the C-terminus of the delivery peptide
• Result: >99% pure conjugate (50 mg) made with preserved activities for both components and easy scale up. 

   

2. Developing strategies for synthesizing cyclic peptide and its conjugate with methotrexate for academic researchers at CellMosaic (shown below).
• Challenge: Need to synthesize a large amount of cyclic peptide and its drug conjugate at a specific site of the drug and peptide. Both peptide and drug are very hydrophobic.
• Labeling strategies:Cyclic peptide and methotrexate are linked together through the lysine amine group of the peptide to one of the two acid groups of methotrexate. Final product is a mixture of two conjugates labeled at either acid. 
• Result: >99% pure conjugate (25 mg) that is easy to scale up. 
3. Developing strategies for synthesizing cyclic peptide and its conjugate with celastrol for academic researchers at CellMosaic (shown below).
• Challenge: Need to synthesize a large amount of cyclic peptide and its drug conjugate at a specific site of the drug and peptide. Both peptide and drug are very hydrophobic.
• Labeling strategies: Cyclic peptide and celastrol are linked together through an amide bond. 
• Result: >93% pure conjugate (25 mg) that is easy to scale up.