Spectrophotometric Analysis for Determining the Average Number of Poly(ethylene) Glycol Molecules on PEGylated Proteins Utilizing a Protein Digestion Step
✍ Scribed by T.H. Barker; M.M. Klinger; D.S. Feldman; G.M. Fuller; J.S. Hagood
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 83 KB
- Volume
- 290
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
The use of resistant and sensitive strains genetically similar is not always possible. A possible blank experiment consists of using a -lactamase inhibitor such as clavulanic acid. In this assay, two samples of 1 mL of the culture (10 7 CFU/mL) were incubated for 30 min at 37°C, one in the absence and the other in the presence of 1 mM clavulanic acid in buffer, pH 7.5. Then, penicillin was added to both to a final concentration of 0.5 mM and incubated for another hour. The ratio of luminescent signal between the sample without clavulanic acid and with it was 1.0 Ϯ 0.3 for the sensitive strain, and 3 Ϯ 1 for the resistant strain. The 1 mM clavulanic acid concentration must not be exceeded since this compound also produces luminescence with the ruthenium complex, negligible at this concentration.