Conformational Studies on Tocinamide and Deaminotocinamide by 220 MHz Nuclear Magnetic Resonance Spectroscopy |
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| Authors: | Anne I. Brewster J. A. Glasel V. J. Hruby |
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| Affiliation: | Bell Laboratories, Murray Hill, New Jersey 07974;*Department of Biochemistry, University of Connecticut Medical School, Farmington, Conn.;†Department of Chemistry, University of Arizona, Tucson, Ariz. |
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| Abstract: | The 220 MHz spectra of tocinamide and deaminotocinamide, the ring moieties of oxytocin and of deamino-oxytocin, respectively, were investigated in [U-(2)H]dimethylsulfoxide solution. Extensive decoupling and exchange experiments allow complete spectral assignment and determination of many coupling constants. Circular dichroism spectra assigned a right-hand screw sense to the C-S-S-C group. The conformations of tocinamide and deaminotocinamide are different from each other and from those suggested for the ring portions of oxytocin and deamino-oxytocin. The relationship of this difference to biological activity is commented upon. The importance of the interaction of the side chain with the ring in oxytocin and deamino-oxytocin is emphasized. |
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