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What Are Peptides? Understanding Peptide Bonds

What Are Peptides? Understanding Peptide Bonds What Are Peptides? Peptides are natural compounds present in all living organisms and are involved in a wide range of physiological processes. The most famous peptide is insulin (molecular structure of insulin on

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What Are Peptides? Understanding Peptide Bonds

What Are Peptides?

Peptides are natural compounds present in all living organisms and are involved in a wide range of physiological processes. The most famous peptide is insulin (molecular structure of insulin on the right), an endogenous hormone for blood sugar regulation. Many other naturally occurring peptides are hormones as well, used as messengers between different systems of an organism to carry information (i.e. glucagon, encephalin, secretin). Others are antimicrobial peptides (i.e. defensin, magainin), or peptide toxins contained in animal venoms.

What is a Peptide Bond?

But what do they look like? Peptides are chains of amino acids (aka biological polymers or oligomers), from 2 to 100 aa and above. Amino acids are linked via peptide (or amide) bonds. Depending on their residue, there are 20 standard natural amino acids. Within a cellular environment, peptides may undergo post-translational modifications such as phosphorylation, acetylation, disulfide bridge cyclization, and many more. A peptide’s sequence, structural composition including its PTMs confer to a wide range of properties allowing the binding to receptors or ligands with a high affinity and specificity.

How Are Peptides Made?

Common Peptide Modifications

Biotinylated and Tagged Peptides

C-Terminal Modifications

Macrocyclic Peptides

Fluorescent Dye Labeled Peptides

Isotope Labeled Peptides

Long Peptide

Peptide Dimers

Peptidomimetics

(PTMs) Post-translational Modifications

Click Chemistry

Cyclic Peptides

Internally Quenched / FRET Peptides

Linker / Spacer / PEGylations

N-Terminal Modifications

Peptide Pooling and Library Service

Protein Conjugates /Immunogenic Peptides

Unnatural Amino Acids

Peptide Applications in Research & Medicine

Peptides have been used for decades in life-science research as laboratory reagents but also as therapeutic compounds, as drug delivery systems, as bio insecticides for agriculture, as biomaterials, as active compounds in cosmetics.

Peptides as Laboratory Reagents

Peptides are commonly used as reagents in all life-science research laboratories and the range of applications is endless. A few noteworthy examples are peptides which are used in vitro on skin cell samples to induce an irritation reaction (referred to as DRPA peptides), which allow cosmetic laboratories to test for irritation properties of compounds.

Peptides are also used in vaccine development to monitor the immune reaction of patients and understand whether a the vaccine has elicited an appropriate immune response.

They are also widely used to understand the binding properties of proteins. For example it is possible to modify some amino acids via chemical synthesis on a protein.

Moreover, they are employed as reference compounds in LCMS/MS SRM and MRM technologies, to accurately quantify and determine proteins, which allows to measure the expression of a biomarker in a tissue or perform DMPK studies of a biological drug. Read up on our peptides in proteomics.

Peptides as Therapeutic Drugs

More than 100 peptides are currently approved within pharmaceutical compositions such including insulin, semaglutide, ocreotide, oxytocin, exenatide, glucagon. Beyond that, thousands of peptides are in development for cancer vaccines, radiopharmaceutical targeted therapies, obesity, pain and more.

Peptides as Drug Delivery System

Peptides have become tools for delivering drugs to specific tissues. Macrocylic peptides containing unnatural amino acids have recently emerged due to progress in the chemical engineering and in silico AI design field. Thanks to their stability, high target specificity, cell-penetrating properties, and easy conjugation to drugs, cyclic peptides are attractive delivery candidates compared to antibody-drug conjugates.

Amphiphilic and hydrogel forming peptides are also used as biomaterials in drug delivery systems to encapsulate the drug and allow for its controlled release; examples include antibiotics, or antimicrobial coated surfaces.

Why Work With JPT?

JPT is a Berlin-based peptide producer based in Berlin sincemanufacturer founded in 2004. With already several mor than a millions of synthesized peptides synthesized per year, JPT is one of the most experienced companies in the world. Currently, thousands of peptides are commonly used by scientists and are available in our catalog. We synthesize all kinds of peptides upon request from 10µg up to several grams. Contact us today!

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Related questions

01Frequently Asked Questions About Peptides

Are peptides legal in the UK? Yes, peptides are legal in the UK for research and scientific purposes. They must be used within strict regulatory standards, ensuring their use is safe and ethical. Are peptides safe? Peptides are well-characterised compounds when handled appropriately in research settings in controlled environments like scientific research or skincare products that adhere to established safety standards. The safety of peptides in other applications, like supplements, depends on compliance with rigorous testing and regulatory standards. Are peptides steroids? No, peptides are not steroids. While both are significant in the biological realm, they differ in structure, function, and use. Peptides comprise amino acids, whereas steroids are a lipid derived from cholesterol. Their roles in the body and research are distinctly different. Can peptides be studied in oral formulations? The oral bioavailability of peptides is a topic of active research. Most peptides break down in the digestive system, which is why research-grade peptides are typically supplied in lyophilised form for laboratory reconstitution. Do peptides work? Peptides are actively studied across many scientific disciplines. Their molecular interactions with cellular receptors and signalling pathways make them valuable research tools in biochemistry and molecular biology. Are peptides studied in reproductive biology? Certain peptides, such as Kisspeptin 10, are studied in reproductive biology research contexts. All research peptides from UK Peptides are for laboratory use only and are not intended for human use. How do peptides work? Peptides interact with cellular receptors and signalling pathways. They can bind to specific receptors on cell surfaces, which is why they are widely studied in molecular biology and biochemistry research. Think of a peptide as a key that, upon finding its specific receptor, unlocks it to produce a targeted result. How are peptides formed and made? Peptides naturally form in the body through protein biosynthesis, linking amino acids together in a specific sequence. In the lab, scientists synthetically create peptides through solid-phase peptide synthesis, which enables precise control over the peptide's composition and sequence.

Source: uk-peptides.com ↗
comparison

Research vs pharmaceutical peptides

Two categories exist: research peptides and pharmaceutical peptides. Research peptides: Sold "for research purposes only" Not FDA-approved for human use 30-95% cheaper than pharmaceutical R…

Source: seekpeptides.com
Research context

Read sources and limitations before applying a claim.

Why Are Peptides So Important in Research?

The peptide research field has grown dramatically for several interconnected reasons. First, improvements in synthesis technology have made it cheaper and easier to produce high-purity peptides in meaningful quantities. Second, advances in analytical chemistry — particularly HPLC and mass spectrometry — have made it possible to verify purity and identity with confidence. Third, the accumulation of decades of basic science research has revealed just how many biological pathways are regulated by peptide signals. Today, peptides are studied across an enormous range of applications: tissue repair (like BPC-157 and TB-500), metabolic regulation (like semaglutide and tirzepatide), anti-aging (like GHK-Cu and NAD+), growth hormone axis research (like sermorelin and ipamorelin), and cognitive function (like selank and semax).

Source: palmettopeptides.com ↗

Published Research Highlights: What Are Peptides Capable of in Clinical Studies?

The scientific literature on research peptides has expanded dramatically over the past two decades. Understanding what are peptides from a clinical evidence standpoint requires looking at the peer-reviewed data. A 2016 study published in the Journal of Physiology and Pharmacology examined BPC-157’s role in tendon healing, demonstrating statistically significant improvements in fibroblast proliferation and collagen organization. The research team noted that BPC-157 promoted outgrowth of tendon fibroblasts from explant cultures, with cells migrating toward the peptide at distances more than 2-fold greater than controls. This research is foundational for anyone investigating what are peptides and their tissue repair applications. For reference, see Sikiric et al., PubMed PMID 10208460. GHK-Cu’s broad gene expression influence was characterized in a landmark genomic analysis by Pickart and Margolina (2018), which found that this peptide modulates the activity of over 4,000 human genes — including genes involved in collagen synthesis, anti-inflammatory signaling, antioxidant defense, and DNA repair. The breadth of these effects reinforces why understanding what are peptides like GHK-Cu at the genomic level is critical for research design. See Pickart & Margolina, Biomedicines 2018, PubMed PMID 29738496. The Phase 2 clinical trial of Retatrutide (Jastreboff et al., 2023, published in The New England Journal of Medicine) enrolled 338 participants across 9 dose groups. At the highest dose (12 mg weekly), participants achieved 24.2% mean body weight reduction at 48 weeks — a result that exceeded both semaglutide and tirzepatide benchmarks in comparable trials. This level of efficacy data illustrates what are peptides capable of in metabolic research. Full trial data: Jastreboff et al., NEJM 2023, PubMed PMID 37379059.

Source: pspeptides.com ↗
Practical and safety references

These excerpts are educational, not personalised medical instructions.

Potential benefits

Benefits of peptides

In this section, we will discuss the anti-aging benefits of peptides, how peptides promote weight loss, and how peptides enhance tissue repair or healing.

Source: driphydration.com ↗
Side effects

Safety Profile and Adverse Effect Considerations

Therapeutic peptides generally exhibit favorable safety profiles compared to small molecule drugs, attributed to their high specificity and natural degradation to amino acids. However, immunogenicity, injection site reactions, and on-target adverse effects require clinical monitoring.

Source: deltapeptides.com ↗
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