Intro to Peptides

Peptide —What Is It?

A peptide refers to an organically occurring chemical compound that contains a minimum of two amino acids that are connected using peptide bonds. On the other hand, a peptide bond refers to a covalent bond that gets formed by two amino acids whenever a c-terminus or carboxyl group of one of the amino acids reacts with an N-terminus of a second amino acid in something called a condensation reaction.

A water molecule is released when this reaction is taking place. The bond formed from this is called a CO-NH bond and is what leads to the formation of an amide molecule or peptide. Similarly, peptide bonds are also called amide bonds. The term “peptide” is derived from a Greek word πέσσειν, which means “to digest.”
Peptides are thus an important part of biochemistry and nature, and that occurs naturally in their thousands in animals and the human body. Additionally, there are new peptides that are being synthesized and discovered in laboratories regularly. As such, the innovation and discovery of peptides hold a big promise for the coming days in the areas of pharmaceutical development as well as in health.

How Do Peptides Get Formed?

As mentioned earlier, peptides are formed synthetically in labs and naturally in the body. The human body is able to organically manufacture peptides like non-ribosomal and ribosomal peptides. Modern peptides synthesized in labs can build a virtually boundless number of peptides through various peptide synthesis methods like solid-phase peptide synthesis and liquid phase peptide synthesis.

Although the latter does offer some benefits, the standard peptide synthesis process in use today is the solid phase peptide synthesis. Emil Fischer discovered the first peptide in 1901 when working in collaboration with Ernest Fourneau. Vincent du Vigneaud synthesized the first polypeptide, oxytocin, in 1953.

A water molecule is released when this reaction is taking place. The bond formed from this is called a CO-NH bond and is what leads to the formation of an amide molecule or peptide. Similarly, peptide bonds are also called amide bonds. The term “peptide” is derived from a Greek word πέσσειν, which means “to digest.”
Peptides are thus an important part of biochemistry and nature, and that occurs naturally in their thousands in animals and the human body. Additionally, there are new peptides that are being synthesized and discovered in laboratories regularly. As such, the innovation and discovery of peptides hold a big promise for the coming days in the areas of pharmaceutical development as well as in health.

Peptide Terminology

The classification of peptides is done based on the number of amino acids they contain. In this case, a peptide containing two amino acids is the shortest, and which is referred to as a “dipeptide.” Similarly, a peptide having three amino acids is known as a “tripeptide.”

Oligopeptides are the term used to refer to shorter peptides that are made up of at least ten amino acids or more. Proteins refer to larger peptides that have between forty to fifty amino acids.

Even though the amount of amino acids contained are the primary determinant when one is trying to differentiate between proteins and peptides, there are instances when exceptions are made.

For instance, various larger peptides have, in some cases, been referred to as proteins, e.g., amyloid-beta. In the same breath, there are other smaller proteins known as peptides, such as insulin.

Although the latter does offer some benefits, the standard peptide synthesis process in use today is the solid phase peptide synthesis. Emil Fischer discovered the first peptide in 1901 when working in collaboration with Ernest Fourneau. Vincent du Vigneaud synthesized the first polypeptide, oxytocin, in 1953.

A water molecule is released when this reaction is taking place. The bond formed from this is called a CO-NH bond and is what leads to the formation of an amide molecule or peptide. Similarly, peptide bonds are also called amide bonds. The term “peptide” is derived from a Greek word πέσσειν, which means “to digest.”
Peptides are thus an important part of biochemistry and nature, and that occurs naturally in their thousands in animals and the human body. Additionally, there are new peptides that are being synthesized and discovered in laboratories regularly. As such, the innovation and discovery of peptides hold a big promise for the coming days in the areas of pharmaceutical development as well as in health.

Peptides Classification

Typically, the peptides are divided into several classes. Classes will, thus, vary depending on how each peptide was produced. For instance, ribosomal peptides are manufactured from mRNA translation. Ribosomal peptides tend to work as hormones and motion particles in animals.

They can include tachykinin peptides, calcitonin peptides, vasoactive peptides, pancreatic peptides, opioid peptides, and intestinal peptides. Antibiotics such as microcins are classified as ribosomal peptides that get produced by numerous organisms. A ribosomal peptide will often go through a process known as proteolysis for them to attain their mature form.

Equally, non-ribosomal particles get produced by certain enzymes that are peptide-specific and not by the ribosome, as is the case with the ribosomal peptides. It’s also important to note that non-ribosomal peptides tend to be cyclic more regularly as opposed to being linear, even though linear non-ribosomal peptides can frequently occur.

The non-ribosomal peptides are capable of developing tremendously complex cyclic structures and regularly occur in one-celled organisms, fungi, and plants. Glutathione is a common non-ribosomal peptide and which is an essential part of the anti-oxidation defenses found in aerobic organisms.

Milk peptides in animals are built from milk proteins. The peptides can be manufactured by the proteinases created by lactobacilli during milk fermentation or during the enzymatic breakdown of digestive enzymes. Furthermore, peptones are the peptides resultant from meat or animal milk that has been processed by proteolytic digestion. Labs often use the peptones as nutrients for growing bacteria and fungi.

Furthermore, the peptide particles are, in many cases, obtained as the products of enzymatic degradation completed in a lab setting when using a controlled sample. On the other hand, peptide fragments can occur naturally due to the degradation caused by natural effects.

Essential Peptide Terms

The following is a look at some of the peptide-related words and terms. They are all central to gaining a generalized understanding of peptide synthesis, peptides, and how peptides are used in research as well as in experimentation.

Peptide Library: A peptide library is one made up of a big number of peptides, all containing a methodical blending of amino acids. Such libraries are put into use when studying proteins for pharmaceutical or biochemical purposes. Peptide libraries are often prepared using a peptide synthesis technique known as the solid phase peptide synthesis.

Amino Acids: Peptides are made up of amino acids. It’s a term used to refer to any molecule containing both carboxyl and amine functional groups. Peptides are constructed from alpha-amino acids.

Peptide Fingerprint: The term peptide fingerprint refers to a chromatographic arrangement of a peptide. It’s created by partly hydrolyzing a peptide, which assists in breaking the peptide into tiny particles. Once complete, it then 2-D maps the resulting particles.

Cyclic Peptides: It refers to a peptide where the amino acid sequence creates a ring structure as opposed to creating a strong chain. Some of its examples include Bremelanotide (PT-141) and Melanotan-2.

Peptide Mimetics: It’s a term used to refer to a molecule that is able to biologically imitate active ligands of bio-molecules, hormones, viruses, cytokines, or enzyme substrates. A peptide mimetic can be a synthetically or naturally modified peptide. It can also be a molecule that is able to perform the functions mentioned.

Peptide Sequence: A peptide sequence refers to the order in which amino acid deposits get attached by the peptide bonds in a peptide.

Peptide Mapping: It’s a process that one can use to discover or validate the amino acid structure of proteins or detailed peptides. The peptide mapping techniques get to accomplish this fete by breaking up the protein or peptide using enzymes. It then examines the resultant configuration of their nucleotide base sequences or amino acids.

Peptide Bond: The term is used to refer to a covalent bond which is fashioned among two amino acids whenever the carboxyl collection of a given amino acid starts to reach with the amino group of the second amino acid. It’s what is known as a condensation reaction, which typically results in the release of a water molecule.

Peptides Vs Proteins

The terms “protein” and “peptide” are commonly confused by their users. The important thing to note is that not all peptide creates proteins; however, all proteins are made up of peptides. Peptides can either be classified according to their source or their functions. There are twenty naturally occurring amino acids that can be combined to form different molecules.

Proteins are, thus, polypeptides (big peptides) that comprise of at least fifty molecules or amino acids comprising of many peptide subunits. Additionally, proteins tend to display a more intricate organization compared to the simple peptides.

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