Polypeptide introduction

Peptide is & alpha- Amino acids are compounds formed by peptide bonds. It is also an intermediate product of protein hydrolysis


Generally, the number of amino acids contained in peptides is two to nine. According to the number of amino acids in peptides, peptides have many different names: compounds formed by dehydration and condensation of two amino acid molecules are called dipeptides. Similarly, there are tripeptides, tetrapeptides, pentapeptides, etc. Peptides composed of three or more amino acid molecules are called peptides. Their molecular weight is less than 10000 da. They can pass through the semi permeable membrane and are not precipitated by trichloroacetic acid and ammonium sulfate. Peptides composed of 2 ~ 10 amino acids are also called oligopeptides (small molecular peptides); Peptides composed of 10 ~ 50 amino acids are called peptides; Peptides composed of more than 50 amino acids are called proteins. In other words, proteins are sometimes called peptides. Polypeptides, also known as peptides, were discovered in the 20th century.