KDEL (amino acid sequence)

KDEL is a sequence in the amino acid structure of a protein which keeps it from secreting from the endoplasmic reticulum (ER). It also targets proteins from other locations (such as the cytoplasm) to the ER. Proteins can only leave the ER after this sequence has been cleaved off. The KDEL sequence is responsible for retrieval of ER luminal proteins from the Golgi apparatus. The abbreviation KDEL is formed by the corresponding letters to each amino acid. This letter system was defined by the IUPAC and IUBMB in 1983, and is as follows:
 * K—Lysine
 * D—Aspartic acid
 * E—Glutamic acid
 * L—Leucine

Therefore, the sequence in three letter code is: Lys-Asp-Glu-Leu.