Proteins are made of simpler structures called amino acids. A chain of amino acids is known as peptides. When two or more amino acids are joined together by a bond, then the resultant structure is termed as a peptide bond. A covalent bond unites two amino acids by means of an amide linkage, this kind of a structure is termed as a dipeptide. A dipeptide linkage is the result of the removal of water from the α-carboxylic group and α- amino group of the two basic amino acids.
A condensation reaction brings out the resultant dipeptide bond between the amino acids. In the case of a tripeptide bond, three amino acids are joined together by utilizing two peptide bonds. Following similar patterns, amino acids can be connected to form diverse structures such as tetrapeptides and so on. An oligopeptide structure results when amino acids are connected following this pattern. When many numbers of amino acids are connected together, then the resulting structure is called polypeptide. Proteins can thus be termed as a polymer of amino acids.
Though the two terms proteins and polypeptides are used interchangeably, low molecular weight structures are termed as polypeptides. Proteins tend to have greater molecular weights.
Proteins are larger sequences of amino acids with more than 50 molecules whereas peptides comprise of less than 50 amino acid sequences. Peptides are classified based on its mode of synthesis. The enzymatic breakdown of milk protein results in the formation of milk peptides. Fermentation of milk results in the production of proteinases by the bacteria lactobacilli which in turn forms the milk peptides.
Milk peptides contribute to antihypertensive effects in animal research studies. The translation of messenger RNA results in the synthesis of ribosomal peptides through proteolysis. The ribosomal peptides function as signaling molecules and hormones. The non-ribosomal peptides such as glutathione are produced by enzymes specific to the peptide. Glutathione is an important component of the functional antioxidants. Peptones obtained by the proteolytic digestion of milk or meat is used to cultivate bacteria and fungi. Peptone is an important constituent of the nutrient media used for the growth of microorganisms.
Biologically active peptides and polypeptides are those peptides that are found in living cells which perform an array of biochemical functions. These biologically active peptides comprise of more than two thousand amino acid residues. Smaller biologically active peptides such as oxytocin, thyrotropin, bradykinin are more functional and perform several important functions. Larger biologically active peptides such as insulin, corticotrophin and glucagon also perform varied biochemical functions. Peptides are now gaining immense prominence in the field of molecular biology owing to their varied functional attributes.
The americansciencelabs.com/melanotan-mt-2 brings about a detailed description of the proteins and peptides through the portals of http://www.academia.edu/5605402/Amino_acid_peptides_and_proteins. Peptides contribute to the production of peptide antibodies by eliminating the need for protein purification. These peptide antibodies are used in several molecular researches on animals. Many studies on the structure, composition and functions of protein are carried out with the help of peptides. Thus, with the growing need of peptides for research, it is imperative to focus on an economical way to obtain peptides for high-end accomplishments.