Editing N-terminus (section)

==Function==

===N-terminal targeting signals===
The N-terminus is the first part of the protein that exits the [[ribosome]] during [[protein biosynthesis]]. It often contains [[signal peptide]] sequences, "intracellular [[postal code]]s" that direct delivery of the protein to the proper [[organelle]]. The signal peptide is typically removed at the destination by a signal [[peptidase]]. The N-terminal amino acid of a protein is an important determinant of its half-life (likelihood of being degraded). This is called the [[N-end rule]].

====Signal peptide====
{{main article|Signal peptide}}
The N-terminal signal peptide is recognized by the [[signal recognition particle]] (SRP) and results in the targeting of the protein to the [[secretory pathway]]. In [[eukaryote|eukaryotic cells]], these proteins are synthesized at the rough [[endoplasmic reticulum]]. In [[prokaryote|prokaryotic cells]], the proteins are exported across the [[cell membrane]]. In [[chloroplast]]s, signal peptides target proteins to the [[thylakoid]]s.

====Mitochondrial targeting peptide====
The N-terminal mitochondrial [[target peptide|targeting peptide]] (mtTP) allows the protein to be imported into the [[mitochondrion]].

====Chloroplast targeting peptide====
The N-terminal chloroplast targeting peptide (cpTP) allows for the protein to be imported into the [[chloroplast]].