Leucine
Leucine is an amino acid which has the single letter amino acid code L, and the 3 letter code Leu. It is a hydrophobic and non-polar amino acid. It is coded for by the nucleotide base sequences: CUU, CUA, CUC and CUG [1].
References:
Berg, J. M., Tymoczko, J. L., & Stryer, L. (2002). Biochemistry (5th ed.). New York: W.H. Freeman.