Nuclear magnetic resonance spectroscopy. Carbon-13 spin-lattice relaxation time measurements of amino acids.
The (13)C spin-lattice relaxation times, T(1)'s, of several amino acids have been measured as a function of pD and concentration. A strong dependence of the carboxyl carbon T(1) was observed for both pD and concentration and is believed to be due to intermolecular associations. For the carboxyl carbon, spin rotation is proposed as the predominant relaxation mechanism, whereas the other carbons are relaxed mainly by the dipole-dipole mechanism, and their relaxation times are relatively independent of changes in concentration and pD.
Alanine↗