Optical and other properties of a hydrocarbon-soluble polypeptide, poly-γ-(n-dodecyl)-L-glutamate
✍ Scribed by Jerry C. Smith; Robert W. Woody
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1973
- Tongue
- English
- Weight
- 482 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
Abstract
The polypeptide poly‐γ‐(n‐dodecyl)‐L‐glutamate (PDLG) is soluble in hydrocarbon solvents such as hexane, cyclohexane, and dodecane. The CD spectra of PLDG in these solvents are reported here. These spectra are typical α‐helix spectra and show none of the wavelength shifts and magnitude changes displayed by partially helical proteins in membrane preparations. This observation rules out the possibility that the membrane protein CD spectra result from solvent effects. The PDLG helix is stable in dodecane up to at least 70 °C. However, it is easily disrupted by trifluoroacetic acid, with the helix–coil transition centered at 3% TFA in hexane. Viscosity measurements of PDLG in dry dichloroacetic acid exhibit polyelectrolyte effects which can be suppressed by addition of several percent water.