Short Peptides Unveiled: Structure, Size, and Functions

Peptides play a crucial role in facilitating timely and high-quality chemical reactions within the body. They act as agents, conveying information from one structural unit to another. Thanks to peptides and the DNA molecule, life continues its course. Together, they establish an extensive system of bioregulation and homeostasis, which might be even older than the endocrine and nervous systems.

Short peptides serve as essential building blocks of the body.

Peptide molecules are constructed from amino acid residues linked together by peptide bonds. These are the structural components of proteins, forming at various stages of their metabolism. In terms of properties and size, peptides fall between high-molecular-weight proteins and amino acids. The diagram below illustrates the formation of a peptide bond:

The segment (-NH-CH-OC-) is called the peptide backbone, a chain of atoms that duplicate. The fragment (-CH-) with an amino acid radical creates a compound (-NH-C(R1)H-OC-), or an amino acid residue. The N-terminal amino acid residue has a free α-amino group (-NH), while the C-terminal amino acid residue also possesses a free α-carboxyl group (OC-).

Peptide Synthesis in the Body

Peptides are present in all cellular organisms, where they are generated within seconds or minutes. They exhibit biological activity and are categorized into groups depending on their actions and origins:

Peptide hormones, synthesized in the hypothalamus (the simplest examples are oxytocin and vasopressin).
Peptides responsible for regulating blood pressure and vascular tone (such as bradykinin and angiotensin).
Neuropeptides (enkephalin).
All oligopeptides are characterized by narrow specialization. Each tissue in the body has its specific peptide. These substances are synthesized in various tissues from amino acids or are formed during protein breakdown.

Every peptide has its precursor – a precursor protein. Peptides are derived from these precursor proteins through hydrolysis. This process takes place in the ribosome under the influence of specific enzymes, complex molecules that accelerate chemical reactions in organisms, facilitating the conversion of one substance into another. Each enzyme speeds up a specific reaction.

For example, there are peptides synthesized in the neurons of the hypothalamus. They reach the pituitary gland via nerve cell extensions, where they coordinate the release of peptide hormones.

Amino Acids, Proteins, and Proteins

Peptides cannot be discussed without considering amino acids and proteins. Amino acids are organic compounds composed of carbon, oxygen, hydrogen, and nitrogen. There are approximately 500 types of amino acids, all sharing a similar structural pattern, represented by the general formula:

H(3) N -CH — COOH…Rn*
*The difference lies in the type of amino acid residue Rn.

Proteins are natural high-molecular-weight organic substances. They consist of α-amino acids linked by strong peptide bonds. The composition of proteins is determined by the genetic code. The synthesis of proteins involves 20 amino acids, which form the standard set.

Proteins can be simple or complex. Simple proteins are called proteins. They are formed solely from polypeptide chains. An example of a complex protein is hemoglobin, a transport protein that contains non-amino acid components (heme b) in addition to the peptide chain.

How Diet and Age Affects Peptide Synthesis

Short peptides are formed at various stages of protein metabolism after ingestion. Under the influence of gastrointestinal tract enzymes (pepsin, gastricsin, renin), protein molecules are broken down into dipeptides and tripeptides. Proteins are found in many foods, including eggs, meat (beef, poultry), fish, and certain plants (peas, beans).

The rate of protein synthesis varies with age. In a young organism, protein synthesis occurs at a faster rate than protein degradation. It takes a cell 1-2 minutes to synthesize a protein molecule consisting of hundreds of amino acids. Age-related changes lead to an imbalance between protein formation and degradation, resulting in a negative balance.

The body’s ability to absorb proteins varies. Protein degradation is optimized by digestive enzymes and acid. Protein synthesis is enhanced through physical exercises performed before meals. To ensure the body receives all the necessary elements, it is advisable to maintain a diverse diet.

The consumption of polypeptides in food can negatively affect the body. The body may perceive long chains of molecules as foreign substances, potentially triggering immune reactions.

Advantages of Short Peptides

Short peptides offer several advantages:

They are absorbed more quickly.
They bypass the prolonged breakdown processes and enter the bloodstream immediately.
They are entirely harmless.

The Role of Peptides in the Body

Peptides play a significant role in the body. They integrate into various cellular structures, enzyme systems, contribute to the functioning of all organs and tissues, and participate in intercellular information transmission. This ensures support for homeostasis and the preservation of intercellular balance. Short peptides exert a positive influence on the immune, nervous, endocrine, and digestive systems. They possess antioxidant properties, strengthen tissues, boost metabolism, and serve as building blocks for protein formation.

Key Functions of Peptides

Peptides perform a diverse range of specific functions:

• By binding to specific regions of DNA, they initiate the synthesis of protein molecules, from which tissues and organs are subsequently formed.
• Peptides are considered regulatory molecules. For instance, short peptides regulate hormonal balance and restore metabolic processes when they deviate from normal. This can occur during illness or after experiencing stressful situations. They actively counteract aging by activating cell regeneration mechanisms and slowing down regressive processes. Additionally, they enhance resistance to damaging agents and regulate gene expression.