1. Signal peptide is a short (5-30 amino acids in length) peptide chain that leads newly synthesized protein to the secretory pathway, and is responsible for guiding protein into subcellular organelles with different membrane structures.

2. The leader peptide, also known as the targeting sequence, is the N-terminal signal of protein synthesized in free ribosomes, and its function is to transport protein.

3. transitpeptide is a leader sequence with 12~60 amino acid residues, which is used to guide protein synthesized in cytosol into mitochondria and chloroplasts.

Extended data

The expression form of foreign proteins in host bacteria such as Escherichia coli is mostly intracellular insoluble expression (inclusion body), and a few are extracellular secretory expression. Using signal peptides to guide the secretion of foreign proteins to specific cell regions can improve solubility and avoid the difficulties caused by renaturation of inclusion bodies.

The signal peptide used in the study comes from the signal sequence of the expression system itself or the exogenous signal sequence, or both. Studies have shown that many foreign genes are secreted and expressed in prokaryotic expression systems, such as Escherichia coli, L- bacteria, Bacillus and Lactobacillus. Signal peptides are also widely used in eukaryotic expression systems, such as Pichia pastoris and insect baculovirus expression systems.

Baidu encyclopedia-signal peptide

Baidu encyclopedia guidance peptide

Baidu encyclopedia-transport peptide