Improving the Heat Resistance of Ribonuclease A by the Addition of Poly(N,N-diethylaminoethyl methacrylate)-graft-poly(ethylene glycol) (PEAMA-g-PEG)
✍ Scribed by Sumon Ganguli; Keitaro Yoshimoto; Shunsuke Tomita; Hiroshi Sakuma; Tsuneyoshi Matsuoka; Kentaro Shiraki; Yukio Nagasaki
- Book ID
- 102467360
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 314 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1616-5187
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✦ Synopsis
Abstract
Poly(N,N‐diethylaminoethyl methacrylate)‐graft‐poly(ethylene glycol) (PEAMA‐g‐PEG) has previously been used as a novel additive to improve the heat resistance of lysozyme, which has a positive net charge and a negatively charged active site. In the present study, we show that PEAMA‐g‐PEG prevents heat inactivation of ribonuclease A (RNase A), which has a positive net charge and a positively charged active site. After treatment at 98 °C for 10 min, the enzymatic activity of RNase A complexed with PEAMA‐g‐PEG was maintained at up to 75% of the level of the native RNase A. The extents of inactivation of RNase A and the complex of RNase A with PEAMA‐g‐PEG were strongly dependent upon the heating temperature and incubation time. Circular dichroism (CD) spectral analysis revealed that heat‐induced irreversible inactivation was largely suppressed when RNase A was complexed with PEAMA‐g‐PEG. These findings suggest that the heat resistance of RNase A is improved by the external addition of PEAMA‐g‐PEG.
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