DURHAM, N.C., Aug. 20 (UPI) -- U.S. bioengineers say a new method they created for attaching a large protective polymer molecule to a protein appears to significantly improve protein drugs.
The Duke University researchers say they've used an animal model to demonstrate the new protein-polymer combinations, known as conjugates, remained in circulation significantly longer than an unprotected protein.
The scientists say their accomplishment represents a new strategy to improve the efficacy of protein drugs.
Unmodified proteins injected into the blood are quickly broken down or cleared by the body's defense system. To get around that problem, drug makers attach another molecule, a polymer known as polyethyleneglycol, to the protein in order to protect it. But that approach has its own drawbacks.
"The current method of combining the two molecules often only works with 10 to 20 percent efficiency, so that a lot of the very expensive starting materials are wasted," said Professor Ashutosh Chilkoti, who led the research.
Chilkoti's approach involved growing the polymer from the protein itself, increasing the efficiency of the protein by more than 70 percent and greatly extending the amount of time it remained active in a living model.
"We also addressed the problem of getting a pure and well-defined product by growing the polymer from a single, unique site on the protein," he said.
The work is detailed in the Proceedings of the National Academy of Sciences.
