In this paper, we have discussed the ^1^3C-{^1H} nuclear overhauser effect (NOE) of amino acids in solids, and pointed out that the transient NOE effect will occur when the ^1^3C spin-lattice relaxation time (T~1^C) is less than the proton spinlattice relaxation time (T~1^H). There are four inequivalent methyls in L- isoleucine solid, and one of them unusually meets the condition of transient NOE effect. We have also discussed this fact in this paper.

Key words: CARBON, METHYL GROUP, AMINO ACID, NUCLEAR OVERHAUSER EFFECTS