CellMosaic offers research and development services for bio-pharmaceutical companies that develop recombinant proteins as therapeutics. New target-specific protein drugs can be developed by conjugating drugs or toxins to recombinant proteins. We can also chemically modify or process your recombinant proteins for better clinical performance with PEG or other classical polymers. CellMosaic's scientists have extensive experience in protein conjugation, purification, and modification. For protein that can be changed at the molecular level, we can use cysteine mutagenesis to introduce a single labeling site. For protein that cannot be changed at the molecular level, we look for specific sites that can be modified using chemical methods (site-specific labeling). For protein that have no site-specific labeling sites, we use controlled labeling of surface amines plus advanced purification to obtain single ratio conjugates or near homogeneous multiple ratio conjugates. 

Advantages of CellMosaic's protein conjugation strategy:

• Freedom to attach drugs via mulitiple methods.
• 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 protein-irinotecan drug conjugate for a bio-pharmaceutical company at CellMosaic (shown below): need to conjugate with a very hydrophobic drug. The protein itself is not very stable and easily precipitated after being conjugated. Manage to obtain clean protein-drug conjugate with minimum aggregation. The conjugate shows a characteristic UV spectrum of irinotecan with absorbance maximum at 360 nm.