The stabilization of vancomycin by peptidoglycan analogs.

The glycopeptide antibiotic vancomycin is unstable in solution. It undergoes a rearrangement involving the conversion of an asparagine residue to isoaspartate to give an antibiotically inactive species, CDP-I. Peptide analogs of bacterial peptidoglycan, such as Ac-D-Ala-D-Ala and di-Ac-L-Lys-D-Ala-D-Ala bind to vancomycin and stabilize the antibiotic against degradation and consequent loss of activity. Protection by peptide is effective even under prolonged heating at 80 degrees C or steam sterilization (30 minutes, 10(4) kg/m2).