The short version of triple helix fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-29. Anything still debated is marked as such rather than presented as settled.
Collagen is a structural protein found in skin, bone, tendon, and cartilage, where it forms a triple helix of three polypeptide chains. The chains contain repeating Gly-X-Y sequences, with proline and hydroxyproline frequently occupying the X and Y positions. Collagen peptides are fragments produced by breaking these long chains through hydrolysis. These fragments vary in length and amino acid composition depending on the source and processing method, so the term covers a range of products rather than a single defined molecule.
Hydrolysis converts native collagen into shorter peptides and improves water solubility. Enzymatic treatment with proteases such as pepsin or alkaline proteases is common, though acid or thermal hydrolysis can also be used. The resulting molecular weight distribution typically ranges from about 2 to 10 kilodaltons. Gelatin is a related product formed by partial hydrolysis, but it retains the ability to gel in water. Collagen peptides undergo further breakdown and generally do not form gels.
Commercial collagen peptides come from bovine hide, porcine skin, fish scales, and fish skin. Each source yields a distinct amino acid profile, including different levels of hydroxyproline and glycine. Marine sources often have lower hydroxyproline content than mammalian sources. Production involves extraction, hydrolysis, filtration, and drying, usually spray drying. The final powder is typically white to off-white and dissolves readily in water. Exact composition and peptide size depend on the raw material and the hydrolysis conditions.
The amino acid profile of collagen peptides is distinctive, with high proportions of glycine, proline, and hydroxyproline. These three residues make up roughly half of the total amino acid content in typical mammalian collagen. Hydroxyproline is formed by post-translational modification of proline and is uncommon in most other proteins. The presence of hydroxyproline serves as a marker for collagen-derived material in analytical testing. Peptide length and distribution depend on the hydrolysis conditions, including temperature, time, and enzyme or acid concentration.
Collagen peptides are typically sold as a powder that dissolves readily in cold or warm liquids. The powder is usually off-white to light yellow and has a mild taste, though some products may have a slight odor. Molecular weight distributions commonly range from about 1,000 to 5,000 daltons, but this varies by manufacturer and intended use. Smaller peptides are generally more soluble, while larger fragments may form viscous solutions. The material is hygroscopic and should be stored in sealed containers away from moisture and heat.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Typical for spray-dried hydrolysates |
| Solubility | Water-soluble | Forms clear solutions at moderate concentrations |
| Molecular weight range | 2–10 kDa | Depends on hydrolysis time and enzyme |
| Storage temperature | 15–25 °C | Keep sealed and protect from moisture |
| Common synonyms | Collagen hydrolysate, hydrolyzed collagen | Not identical to gelatin |
Quality control for hydrolyzed collagen begins with identity testing and raw material traceability. Laboratories may verify protein content by Kjeldahl or combustion methods, and characterize molecular weight distribution using size-exclusion chromatography or gel electrophoresis. Amino acid analysis confirms the presence of glycine, proline, and hydroxyproline in expected proportions. Moisture, ash, and microbial limits are also monitored because powders can absorb water. These tests help distinguish hydrolyzed collagen from gelatin, whey, or plant protein ingredients.
Stability depends on moisture, temperature, and packaging. Dry powders are generally stable for months to years when kept sealed and cool, but heat and humidity can promote clumping, Maillard reactions, and off-flavors. Peptides with lower molecular weight may be more hygroscopic than longer-chain hydrolysates. Light exposure is less critical than moisture control for most commercial powders. Once a container is opened, repeated exposure to air can shorten usable shelf life.
Analytical results are method-dependent, so comparisons across studies require caution. Different molecular weight cutoffs, standards, and calculation models can shift reported averages. Hydroxyproline content is sometimes used as a marker for collagen-derived material, but it does not reveal peptide sequence or biological activity. Regulatory status varies by country and intended use, with some markets treating hydrolyzed collagen as a food ingredient and others as a dietary supplement. Open questions include how to standardize potency and verify claimed peptide profiles.
Quality testing of collagen peptides relies on several analytical methods. Molecular weight distribution is commonly measured by size-exclusion chromatography, sometimes paired with multi-angle light scattering. Amino acid composition is determined by ion-exchange chromatography or reversed-phase high-performance liquid chromatography after acid hydrolysis, while protein content is estimated by Kjeldahl or Dumas nitrogen analysis. Moisture, ash, and heavy metals are checked against specification limits. These tests help ensure consistency and detect adulteration with other proteins.
Regulatory treatment of collagen peptides varies by country and intended use. In the United States, they are typically marketed as dietary supplements or food ingredients, and certain uses may be generally recognized as safe (GRAS) through self-affirmation or notification. In the European Union, collagen peptides from approved animal sources are considered food, not novel foods, if they have a history of consumption. Health claims linking collagen peptides to joint or skin benefits are not approved in the US or EU. Labeling must list the animal source and may state the protein content.
Manufacturing collagen peptides begins with collagen-rich raw materials such as bovine hide, porcine skin, fish scales, or poultry cartilage, which undergo washing, size reduction, and pretreatment to remove non-collagen proteins and fats. Extraction may use acid, alkali, or heat. Hydrolysis then breaks the collagen into smaller peptides, often with enzymes such as pepsin, papain, or alcalase. Process conditions of time, temperature, pH, and enzyme dose determine the final molecular weight distribution. After hydrolysis, the solution is filtered, concentrated, and dried into powder.
One challenge in collagen peptide analysis is the absence of a single reference standard that covers all possible molecular weight fractions. Products from different sources or hydrolysis conditions yield different peptide profiles, complicating direct comparisons. Some laboratories use gelatin or a defined peptide mixture as a calibration standard, but this approach has limitations. Additionally, the term "collagen peptide" itself lacks a universally accepted molecular weight cutoff. Ongoing discussions aim to establish more consistent definitions and testing protocols for regulatory and research purposes.
Quality control of collagen peptides relies on methods that characterize molecular weight distribution, amino acid composition, and purity. Size exclusion chromatography (SEC) is commonly used to estimate the molecular weight profile of peptide mixtures. High-performance liquid chromatography (HPLC) can separate and quantify individual peptide fractions. Mass spectrometry provides detailed information on peptide sequences and modifications. These techniques help verify that a product meets declared specifications, though standardization across laboratories remains limited.
Additional tests assess moisture, ash, and nitrogen content to confirm overall composition and processing consistency. Heavy metal analysis, including lead, arsenic, cadmium, and mercury, is performed to ensure limits are not exceeded. Microbial testing checks for total aerobic counts, yeast, mold, and specific pathogens such as Salmonella and Escherichia coli. These safety parameters are often required by regulations for food or dietary supplement ingredients. Results are compared against internal or pharmacopeial specifications, which may differ between jurisdictions.
=== Constituent assembly === One of Castillo's principal goals is to convene the constituent assembly to repeal and rewrite the Fujimori-era constitution. This measure is unlikely to pass in an opposition-controlled Congress. However, Free Peru and the Vice President have been collecting signatures to enact a constituent assembly via referendum. Likewise, the opposition has been gathering signatures against the proposal. Legal experts doubt whether these signatures will allow a constituent assembly to be held. Following the resignation of the Bellido cabinet, Prime Minister Mirtha Vásquez stated that changing the constitution is not a priority, despite it having been one of Castillo's main campaign promises. On 1 December 2021, Free Peru's spokesperson Waldemar Cerrón criticized a proposed Congressional bill which would require constitutional reforms to be "approved by Congress with an absolute majority of the legal number of members" to be submitted for referendum. This proposal would restrict the powers of the constituent assembly.
. Chemical engineers once used the kilogram-mole (notation kg-mol), which is defined as the number of entities in 12 kg of 12C, and often referred to the mole as the gram-mole (notation g-mol), then defined as the number of entities in 12 g of 12C, when dealing with laboratory data. Late 20th-century chemical engineering practice came to use the kilomole (kmol), which was numerically identical to the kilogram-mole (until the 2019 revision of the SI, which redefined the mole by fixing the value of the Avogadro constant, making it very nearly equivalent to but no longer exactly equal to the gram-mole), but whose name and symbol adopt the SI convention for standard multiples of metric units – thus, kmol means 1000 mol. This is equivalent to the use of kg instead of g. The use of kmol is not only for "magnitude convenience" but also makes the equations used for modelling chemical engineering systems coherent. For example, the conversion of a flowrate of kg/s to kmol/s only requires dividing by the molar mass in kg/kmol (which is equivalent to g/mol, as
==== United States ==== Between 1973 and 1978, eleven states decriminalized marijuana. In 2001, Nevada reduced marijuana possession to a misdemeanor and since 2012, several other states have decriminalized and even legalized marijuana. In 2018, surveys indicated that almost half of the people in the United States had tried marijuana, 16% had used it in the past year, and 11% had used it in the past month. In 2014, surveys said daily marijuana use amongst US college students had reached its highest level since records began in 1980, rising from 3.5% in 2007 to 5.9% in 2014 and had surpassed daily cigarette use. In the US, men are over twice as likely to use marijuana as women, and 18–29-year-olds are six times more likely to use as over-65-year-olds. In 2015, a record 44% of the US population has tried marijuana in their lifetime, an increase from 38% in 2013 and 33% in 1985. Marijuana use in the United States is three times above the global average, but in line with other Western democracies. Forty-four percent of American 12th graders have tried the drug at least once, and the typical age of first-use is 16, similar to the typical age of first-use for alcohol but lower than the first-use age for other illicit drugs. A 2022 Gallup poll concluded Americans are smoking more marijuana than cigarettes for the first time.
=== Editorial === Bhatt was Senior Associate Editor for News and Clinical Trials for ACC.org, member of the Healio | Cardiology Today Editorial Board, and Editor-in-Chief of the Journal of Invasive Cardiology, which also lists him as:
Sources: en.wikipedia.org
Prohibitin, also known as PHB, is a protein that in humans is encoded by the PHB gene. The Phb gene has also been described in animals, fungi, plants, and unicellular eukaryotes. Prohibitins are divided in two classes, termed Type-I and Type-II prohibitins, based on their similarity to yeast PHB1 and PHB2, respectively. Each organism has at least one copy of each type of prohibitin gene.
=== Precision medicine === Graphene oxide has been studied for its promising uses in a wide variety of nanomedical applications including tissue engineering, cancer treatment, medical imaging, and drug delivery. Its physiochemical properties allow for a structure to regulate the behaviour of stem cells, with the potential to assist in the intracellular delivery of DNA, growth factors, and synthetic proteins that could allow for the repair and regeneration of muscle tissue. Due to its unique behaviour in biological environments, GO has also been proposed as a novel material in early cancer diagnosis. It has also been explored for its uses in vaccines and immunotherapy, including as a dual-use adjuvant and carrier of biomedical materials. In September 2020, researchers at the Shanghai National Engineering Research Center for Nanotechnology in China filed a patent for use of graphene oxide in a recombinant vaccine under development against SARS-CoV-2.
Thus an antigen might bind specifically to a T or B cell receptor, but not induce an adaptive immune response. If the antigen does induce a response, it is an 'immunogenic antigen', which is referred to as an immunogen.
Sources: en.wikipedia.org
=== Size exclusion chromatography === Izon Science produces a range of size-exclusion chromatography (SEC) columns called ‘qEV columns’ that separate extracellular vesicles from other constituents in a wide range of biological sample types. qEV columns are packed with a porous, polyacrylamide resin, which facilitates the separation of bio-molecules and particles in a solution based on size. Once a sample is loaded onto the column, the sample passes through the resin under the force of gravity. Larger particles elute the earliest, as they cannot enter the pores in the resin and therefore take a more direct route down the column. In contrast, particles smaller than the designated cutoff size (35 nm or 70 nm, depending on the qEV column) enter pores in the resin and elute later. The sample exits the bottom of the column and is collected into collection tubes placed in the Automatic Fraction Collector, or through manual collection.
=== Arnold Adolph Berthold (1849) === Arnold Adolph Berthold was a German physiologist and zoologist, who, in 1849, had a question about the function of the testes. He noticed in castrated roosters that they did not have the same sexual behaviors as roosters with their testes intact. He decided to run an experiment on male roosters to examine this phenomenon. He kept a group of roosters with their testes intact, and saw that they had normally sized wattles and combs (secondary sexual organs), a normal crow, and normal sexual and aggressive behaviors. He also had a group with their testes surgically removed, and noticed that their secondary sexual organs were decreased in size, had a weak crow, did not have sexual attraction towards females, and were not aggressive. He realized that this organ was essential for these behaviors, but he did not know how. To test this further, he removed one testis and placed it in the abdominal cavity. The roosters acted and had normal physical anatomy. He was able to see that the location of the testes does not matter. He then wanted to see if it was a genetic factor that was involved in the testes that provided these functions. He transplanted a testis from another rooster to a rooster with one testis removed, and saw that they had normal behavior and physical anatomy as well. Berthold determined that the location or genetic factors of the testes do not matter in relation to sexual organs and behaviors, but that some chemical in the testes is being secreted is causing this phenomenon.
The news media focused on Nixon's militaristic tone, describing his announcement with variations of the phrase "war on drugs". The day after Nixon's press conference, the Chicago Tribune proclaimed, "Nixon Declares War on Narcotics Use in US". In England, The Guardian headlined, "Nixon declares war on drug addicts." The US anti-drug campaign came to be commonly referred to as the war on drugs; the term also became used to refer to any government's prosecution of a US-style prohibition-based drug policy. Facing reelection, with drug control as a campaign centerpiece, Nixon formed the Office of Drug Abuse Law Enforcement (ODALE) in late 1971. ODALE, armed with new federal enforcement powers, began orchestrating drug raids nationwide to improve the administration's watchdog reputation. In a private conversation while helicoptering over Brooklyn, Nixon was reported to have commented, "You and I care about treatment. But those people down there, they want those criminals off the streets." From 1972 to 1973, ODALE performed 6,000 drug arrests in 18 months, the majority of the arrested black. In 1972, the Shafer Commission released its report, "Marihuana: A Signal of Misunderstanding", comprising a review of the medical literature and a national drug survey. It recommended decriminalization for personal possession and use of small amounts of cannabis, and prohibition only of supply. The conclusion was not acted on by Nixon or by Congress.
== Research == Under research are GLP1 poly-agonist peptides, dual and triple receptor agonists such as tirzepatide (GLP-1 + GIP) and retatrutide (GLP-1 + GIP + glucagon), and combinations such as cagrilintide/semaglutide, which combines semaglutide with a dual amylin and calcitonin receptor agonist, and amycretin, which acts as both a GLP1 and an amylin agonist.
Sources: en.wikipedia.org
Collagen peptides are short chains of amino acids made by hydrolyzing native collagen. They are water-soluble and do not form gels like gelatin.
Gelatin is partially hydrolyzed collagen that can form a gel in water. Collagen peptides are further broken down into smaller fragments and remain soluble without gelling.
No. Native collagen is a large triple-helical protein, while collagen peptides are fragmented and lose the triple-helical structure. The two differ in molecular size, solubility, and behavior.
They are produced by hydrolyzing collagen extracted from animal tissues, most commonly bovine hide, porcine skin, fish scales, or eggshell membrane. The source material determines the amino acid profile and may affect allergenicity.