The structure and chemical integrity of a peptide plays a strong role in the way that this peptide interacts with biological components. Peptides may be designed to interact with specific cells or tissues, and are therefore given the opportunity to bond or break—based on the needs of these areas. The way a peptide breaks or continues to bond with structures throughout the body will determine the biological process that is completed as well as the success of this function once it has begun.
The ability to create peptides with sound bonds is essential both to natural peptides formed by the body and synthetic peptides that are applied to animals for research purposes. The sooner a chemical bond within a peptide is broken, the shorter the effective life of this peptide will be.
If a peptide does not have an effective structure, it may be vulnerable to damage on the shelf, which can alter research data or create unexpected side effects in animal test subjects upon the chemicals being applied. There are a variety of products and chemical methods that are used to address this growing need to ensure that peptides that could one day be used for pharmacological purposes will behave in a consistent manner.
3.5.5 Discuss the relationship between one gene and one polypeptide:
Ipam is an abbreviation for NNC 26-0161 more commonly known as ipamorelin, a polypeptide hormone that acts as a secretagogue and mimic to ghrelin that was developed by Novo Nordisk.
- This synthetic peptide was developed in the 1990s as part of a group of peptides designed to mimic GHRPs that are developed within the bodies of animals. Ipam is capable of encouraging an animal’s body to release a large amount of growth hormone without the need for additional peptides to be present. This is because the peptide suppresses somatostatin which normally acts as an antagonist to GHRH and stimulates the anterior pituitary to release growth hormone the way GHRP-6 or GHRP-2 would.
- Similar to GHRP-2, Ipam does not affect the lipogenic properties of ghrelin, but unlike GHRP-6 Ipam does not induce hunger in the animals when it is applied.
- Ipam can act synergistically if it is applied while natural GHRH is present in an animal’s system or when it is administered alongside a GHRH analog or GHRH itself. Common analogs include GRF 1-29 or semorelin.
- The synergy of these peptides stems from the somatostatin suppression and the increase in growth hormone per somatotrope. GHRH increases somatotropes that increase growth hormone but Ipam creases a neuronal excitation of the animal’s hypothalamus that can last up to 3 hours after the chemical is applied. This is a similar reaction to GHRP-2 or GHRP-6.
- Compared to other chemicals in the GHRP family, Ipam has a unique set of properties known as selectiveness. In one study growth hormone secretagogue acted with an increasing efficiency and potency in vivo and in vitro. This led to the chemical being identified as one of several compounds that lacks the central dipeptide ala-trp that is commonly seen in GHRP-1.
- Ipamorelin caused growth hormone releases in the pituitary gland of rats in vitro—with a similar potency of GHRP-6—which allowed researchers to profile this chemical as a growth hormone releasing hormone with an antagonist structure that was capable of stimulating growth hormone via the GHRP receptors.
- Research in pentobarbital rats that were anaesthetized, Ipam was capable of causing a release of growth hormone that was just as efficient and potent as the reaction from GHRP-6. This reaction was once again seen in swine that were conscious during study, with Ipam releasing growth hormone in the plasma at a rate that is quite similar to GHRP-6. However, in this case there was a higher potency of growth hormone when GHRP-2 was applied, though the efficacy was lower.
- In swine, none of these growth hormone secretagogues affected TSH, FSH, PRL or LH levels in the plasma. Administering GHRP-2 and GHRP-6 increased cortisol and ACTH levels in the plasma but there was no release of ACTH or cortisol levels when Ipam was administered in levels that were 200 times higher than the ED50 for growth hormone release. This research indicates that Ipam would be an ideal candidate for further study for clinical development.
- GHRP-2 and GHRP-6 are not capable of increasing prolactin or cortisol levels but Ipam can selectively release growth hormone, regardless of the size of the application. Mega-applications of Ipam can create a mega-release of growth hormone which can allow the body to release the entire amount of the hormone currently stored in the pituitary gland of the animal. GHRP-6 and GHRP-2 are only capable of allowing an animal’s body to release around 1mcg/kg of growth hormone regardless of how much of the chemical is applied.
- The pharmaceutical industry is particularly interested in any research that assists with targeting or identifying the properties of bioactive peptides in more complex matrices. This can help to assess the feasibility of these peptides in supercritical fluid chromatography of the separation of two pairs of water soluble peptides with the same composition, mass and charge which are only differentiated by the sequence of their amino acids. Evaluating a variety of these conditions, including the conjunction of trifluoroacetic acid, may be the most effective model in noting the elution of isometric pairs of peptides in nitrogenous stationary phases.
- By contrast to this methodology, ammonium acetate and water can create peak shapes in these measurements which are found to be less ideal than additives that are neutral. Basic additives such as iso-propylamine combines with HA-Pyridine can create a high resolution factor that can complete a study on the given peptides. It was found that aminopropyl and HA-pyridine created the best resolution for evaluating these peptide pairs while phenyl-hexyl and silica did not allow for the necessary separation.
- Carbon dioxide and a methanol modifier have been found to assist with peptide solubility transport with stationary phase solvation while HTFA helped to fully protonate the peptide pairs from their ion pair to conjugate the based cationic peptide analate. This separation process was found to be the ideal ion pair supercritical fluid chromatography for this method with Ipam providing the ideal resolution for HA-Pyridine columns for peptides in a neutral state.
Analytial and preparative scales include supercritical fluid chromatography that indicate a widespread applicability for separating chirals of polar pharmaceutical candidates, but this technique is quickly becoming achiral because there is a larger utility for separating ionic analyates, like organic sulfonates and amine salts.
The key to this is including additives like ammonium acetate and trifluoroacetic in the mobile phase of associating with the stationary silica and evaporative light scattering detection. This method was found to create a .3 TFA in methanol and .2 TFA in 90:10 methanols: water and a spike with a 90:10 ratio of Ipam and methanol.
Protein Synthesis, Translation (1):
Protein Synthesis, Translation (2):
Protein Synthesis, Translation (3):
Insulin Growth Factor
Insulin-like growth factor or IGF most commonly refers to somatomedin C or IGF-1 which is a protein that is encoded using the IGF1 gene.
- IGF based peptides contain a large group of chemicals that are used in an animal’s body to communicate physiologic environmental changes or needs. To achieve this, IGF molecules have to cell-surface receptors and ligands which are arranged in a variety of ways, allowing for a six-high affinity of binding proteins and IGFBP degrading enzymes, known as proteases.
- The axis of an IGF molecule is known as the growth hormone/IGF-1axis. IGF-1 is typically secreted by an animal’s liver when it is stimulated by growth hormone and used for regulating the physiology of the body and preventing pathological problems such as cancer. The axis helps to maintain cell proliferation and inhibits cell death when possible.
- IGF-2 is believed to be a primary growth factor that is essential to the early expression of growth hormone while IGF-1 is used to maximize the growth of tissues. Studies on mice have noted these differences and also helped the scientists to realize that IGF-2 is primarily shown in the fetal animals rather than in full grown animals as a means of developing the kidney, brain or liver.
- There are systems which can vary the expression of IGF-1 and growth hormone in the circulation. This may include the genetic makeup of the animal, its sex, age, amount of exercise, nutrition level, stress level, disease state, species, body mass index, xenobiotic intake and estrogen status, among others. IGF-1 is found to regulate the development of neurons— including those for synaptogenesis, neurogenesis, myelination and dendritic branching. It can also be seen assisting with neuroprotection after neurons have been damaged. Children with a higher IQ have been found to have higher levels of serum IGF-1.
- The development of cochlea is also impacted by IGF-1 by managing apoptosis. A deficit of IGF-1 for this system can result in hearing loss. There appears to be a correlation by a lack of IGF-1 and a reduction of hearing and short height in young animals or those entering some form of puberty.
- There are a variety of types of IGF receptors so it can be difficult to narrow down the distinct types of tissues that are affected by IGF-1, particularly when comparing reactions amongst different species of animals. The role of IGF-1 as a neurotrophic factor is perhaps the most well-known because it is easy to tract its induction of survival neurons. In many animals IGF-1 also causes hypertrophy in skeletal muscle because it induces protein synthesis that can block atrophy. In many cases IGF-1 can also protect cartilage by activating osteocytes that can act as an anabolic factor for bone cells. In very high concentrations IGF-1 can act as an insulin receptor and compliment the effects of insulin that is also present in an animal’s system.
- The tissues in an animal’s body will display a variety of IGF-1 receptors based on the effects that would best impact this tissue and induce survival of the neurons that are present in this area of the animal’s body. Common reactions that affect this phenomenon include hypertrophy in skeletal muscle, blocking muscular atrophy protecting cartilage and inducing the synthesis of proteins. IGF-1 is also associated with activating osteocytes which could be anabolic in some animals.
- Both IGF-1 and IGF-2 are regulated by proteins, known as IGF-binding proteins, which are used by animals’ bodies to modulate the IGF receptors that can work both as a means to inhibit IGF by simultaneously promoting the use of IGF in theory by helping the delivery of the chemical to the receptors so that the half-life of IGF-1 is increased. Current data suggests that IGFBPs are essential to the ability of an animal to regulate IGF once it has been activated.
- Recent studies indicate that the IGF/insulin axis is essential to the aging process. Fruit flies and nematodes amongst other animals show an increase in their lifespan when their version of insulin that mimics the gene in mammals is eliminated. It is somewhat difficult to replicate these results in mammals because the production of insulin is linked to a variety of genes and therefore cannot be completely eliminated.
- Simple organisms have fewer IGF-1 receptors and in many cases the roles of these insulin types are unknown. This is largely because these organisms lack specialized organs that would require insulin to react as part of a glucose homeostasis reaction. In addition to this IGF-1 has been found to cause dauer formation to developmental stage C in nematodes which will affect the lifespan of the animal when it is in the larva stage, a situation that lacks any correlation with mammals. Because of this lack of correlation between species it is unclear whether or not IGF-1 will perturb aging in mammals though there is some indication that the phenomena may be related to restrictions in the diets.
- Additional studies are currently ongoing to determine to determine how IGF impacts diseases such as diabetes or cancer. It is currently indicated that IGF may impact the growth of breast or prostate cancer cells though researchers are not currently able to agree how IGF-1 plays a role in this process.
Current difficulties are posed to those that are studying the impact of IGF-1 and IGF-2 and how these things could be utilized in future pharmacological settings because there is such a variance in how these peptides behave in different types of animals.
Today, researchers are not yet ready to begin testing IGF based applications on human test subjects, but the variance of reactions in test subjects such as swine, emus, insects or rats make it difficult to narrow down what types of applications would even be appropriate for human test subjects. In some cases, the use of synthetic human tissues or tissue samples have been helpful in moving around this obstacle until more definitive data can be confirmed.
Structural Integrity of the Blends
Peptides, both short and long, rely on their natural structural integrity to interact with tissues and complete biological tasks, and this is something that a synthetic peptide will need to address in order to have biological significance.
- Data from a variety of animals or human tissue samples indicate that the integrity of myelin sheaths will deteriorate during normal aging, which can result in neural networks that are commonly found throughout the body to become disconnected or otherwise disrupted. This phenomenon can be viewed using an MRI, which is typically used as a way of accessing the impact of things such as Alzheimer’s disease on the brain and other neurological tissues. Evaluating the affected tissues early can help to determine the condition of the genu and the splenium to determine both the presence of the disease as well as the most effective means of addressing these complications.
- Calculating the transverse relaxation rates using an indirect measure of the white matter and the structural integrity of these neurological formations. The relationship between the splenium and genu differed in two main regions of the animal brain. The quadratic function was used to show the accelerating rate of decline in structural integrity starting around 31. The genu was found to deteriorate while the splenium decline was more gradual or liner. This indicates that age related structural damage is heterogeneous and consistent with the myelin properties that are more susceptible to the aging process.
- The function of the brain and signaling throughout the body is also largely reliant on peptides and the release of hormones stimulated from this chemical for normal bodily function in animals. As the aging process begins to impact the structural integrity of animal tissues, the proper function and integrity of the peptides throughout production may also be impacted. Research into these matters will often focus on developing synthetic peptides that could potentially help avert the damage to animal tissue, as a result of such structural damage from the aging process.
- Throughout the past decade there has been a distinct increase in the discovery of bacteria that are resistant to antibiotics, organisms that are generally classified as “superbugs.” These bacteria cannot be killed with current antibiotics that are approved for human use, which poses a threat to public safety, resulting in a pressing need to introduce new, effective medications into the market.
- One potential solution for addressing the growing problem surrounding a lack of credible antibiotics is to generate medications that rely on antimicrobial peptides. These peptides are isolated from living entities which use these peptides to create a defense against bacteria and other organisms that can invade an animal’s body and cause illness. Based on a template of the natural peptide, a variety of antimicrobial cationic peptides can and have been designed to combat pathogens. Each of these peptides can be designed with a diverse structure biologically and chemically, to address specific microbial threats or to be used on different types of organisms for antimicrobial purposes.
- The key to this research is developing new peptide structures that will mimic the natural peptide so they are not rejected by the body, directly address the threat of the incoming microbe and do not pose a potential for dangerous side-effects once they are applied to the animal. Because of these concerns, few peptides have entered clinical animal trials to date, and had success at this stage. The short half-life of many peptides poses a concern when it comes to applying these peptides or storing them in a pharmaceutical setting for medical use later. However, the wide range of biological activities, structures, activity spectra and mode of action those peptides possess shows potential that these issues will be addressed in time.
- Self-assembly and mineralization of peptide nanofibers shows some potential to addressing the issue of creating peptides that are capable of maintaining their structures for an increased length of time. pH induced self-assembly has been applied to peptide amphiphiles to create a scaffold of nanostructured fibers that is similar to an extracellular matrix. This allows the nanofibers within the peptide to be cross-linked in a reversible manner to decrease or enhance structural integrity as necessary.
- After the fibers are cross linked they can be subjected to hydroxyapatite or mineralization directly to create composite minerals that have crystallographic c axes of the hydroapatite are aligned with the fiber’s long axes. This alignment is identical to that which would be seen between hydroxyapatite crystals and collagen in an animal’s bone.
Both long and short peptides are designed to be broken down by the animal’s body as a means of harvesting the chemicals used to create the molecule during biological processes. In some cases, peptides will break down into smaller molecules or peptides that are capable of creating additional processes within the body after their initial task has been completed. Due to this phenomenon, long peptides generally have a more fragile structure than those of the short variety. Understanding where peptides are designed to break and what enzymes or biological interactions can cause damage to the structure of a peptide will help researchers develop synthetic peptides with reinforced or purposely weakened structures that can be used to alter the way the peptide interacts with animal tissues.
Tadalafil is a PDE5 inhibitor that is researched for its ability to address erectile dysfunction in mammals.
- Originally tadalafil was developed by ICOS but it is now sold worldwide by Lilly ICOS LLC for research purposes. This peptide can commonly be applied to animal test subjects in 40mg applications for best and most accurate results. In some cases tadalafil will be manufactured as Tadacip when it is manufactured in India or provided in smaller applications.
- Tadalafil is often sold under the name Cialis or Adcira for its potential in addressing pulmonary arterial hypertension or benign prostatic hyperplasia. This refers to a combination of erectile dysfunction and benign prostatic hyperplasia that have coincided.
- Penile erection as a result of sexual stimulation is caused by a relaxation of the penile arteries and the corpus cavernosum muscles to allow blood flow to increase to this area. Nitric oxide may mediate this response from the endothelial and nerve terminals to stimulate the synthesis of cGMP in the muscle cells. Smooth muscle can be relaxed by Cyclic GMP to increase the blood flow within the corpus cavernosum.
- Inhibiting phosphodiesterase 5 (PDE5) can help to increase the function of the penis and its ability to achieve an erection by increasing the presence of cGMP, a process that tadalafil is designed to achieve.
- Because sexual stimulation must be present to release nitric oxide, the inhibition of PDE5 from tadalifil will not have any sort of effect on the function of an animal’s penis without sexual stimulation of some kind being present, which is why this peptide is currently administered to animals just prior to sexual activity with an increase in application size as the animal becomes tolerant of the substance.
- This current application schedule would not be effective in a pharmacological setting. Men that would require tadalifil for treatment of erectile dysfunction would need to plan their use of the drug and schedule sexual activities accordingly, which in many cases would not be an effective means in achieving a healthy sex life. To address this problem, clinical trials on animal subjects are currently attempting to determine if it would be possible to create an application of this peptide that could be taken once daily for those that suffers from chronic erectile dysfunction. Some European markets are also attempting to lower the application size of Cialis as a means of allowing humans to use this chemical as part of a therapy for erectile dysfunction, though the product is not yet ready for human use. The potential risks and benefits of these types of applications are currently unknown.
- A variety of trials have been performed on many types of mammal test subjects to determine the side effects of different sized applications of tadalafil. The most commonly seen irritations include muscle aches, back pain, headache, indigestion, flushing of the skin or runny nose. Most of these side effects are conjectured based on the behavior of the given animal. The effects of tadalafil appear to fade after a few hours, though some side effects appear to last as long as 48 hours depending on the size of the application.
- The FDA has discovered that applying tadalafil can lead to vision impairment caused by nonarteritic anterior ischemic optic neuropathy in some test subjects. Most animals that showed signs of this development had underlying vascular or anatomic risk factors that researchers were unaware of when the chemical was first applied. Animals that are older or already show signs of coronary artery disease, diabetes, hyperdension, hyperlipidemia or were exposed to smoke have an additional risk for this side effect. Because so few test subjects showed these signs and were exposed to a variety of factors that could have impacted their vascular health, no conclusions were drawn regarding the dangers of tadalafil on NAION. However, because this trend was noted, any similar PDE5 inhibitors that are already on the market for human use are now required to carry a label that warns of this possible association and doctors must discuss this potential risk with erectile dysfunction patients that hope to receive a prescription to manage their condition.
- In studies tadalafil is commonly compared or introduced with other medications. This can help researchers better determine any risks that may be posed to those using this chemical if it enters the market, particularly if there is success in creating a daily form of tadalafil for chronic conditions. It is currently known that PDE5 inhibitors cause transiently low blood pressure, so it cannot be used along with organic nitrates. Those that are exposed to organic nitrates within 48 hours of an application of tadalafil are at risk for hypotension that could be life threatening. This would be difficult for any humans hoping to use a future daily form of this chemical if they suffered from angina as paramedics would not be able to use many common medications to assist them in the case of an emergency. This issue is one of the concerns that is inhibiting the acceptance of a regular application of tadalafil for humans.
- Predominantly tadalafi is seen to metabolize with hepatic CYP3A4 enzyme systems. The presence of any other chemicals or existing medications that would induce this type of reaction in an animal has been seen to lower the half-life of tadalafil and create a significant reduction in serum levels. This has been seen repeatedly in animal trials.
When compared to similar PDE5 inhibitors including vardenafil and sildenafil, there are a variety of reactions that differentiate tadalafil. Vardenafil and sildenafil are capable of inhibiting PDE6 which is found in the eyes whereas tadalafil is less effective. Sildenafil test subjects are also reported to be more sensitive to light because of this inhibition to PDE6 and have a blue tinge that other test subjects do not.
Vardenafil and sildenafil are also more effective than tadalafil in inhibiting PDE1 which is in the vascular smooth muscle, heart and brain which increases the instances of flushing, vasodilation and tachycardia in test subjects. By contrast, tadalafil is more effective in inhibiting PDE11 than the other PDE5 inhibitors.
Inexpensive Peptide Supplier
Getting the most for your money is essential when investing in peptides for long term research to ensure that there is an adequate supply of chemicals available for large sample sizes and long term trials.
- Much of the cost of manufacturing peptides has little to do with the ingredients necessary to create the compounds as great deal of these peptides are created from very basic materials that are readily available. Much of the cost of preparing a peptide for sale involves researching the potential uses of this peptide in the research market. Most companies that produce peptides are also performing trials of their own to determine their functionality and how they impact the biological processes that animals require to produce and maintain healthy tissues.
- Research into peptides available for sale also depends on creating peptides that can easily be shipped to other research facilities without incident. In animal tissues peptides often have a very short half-life that lasts only a few seconds, just long enough to trigger the necessary biological process, before they are broken down and absorbed by the tissue to take advantage of the nutrients contained in the peptide. In some cases peptides will break down into other molecules that can trigger other biological processes, such as those peptides that trigger muscle growth and hunger, which can impact how a peptide will behave in a research setting. Minimizing this breakdown before the peptide is applied to the animal test subject is essential to getting accurate test results from the product.
- To ensure that there are minimal side effects or breakdown of the chemicals in a research peptide, many companies have altered the structure of a synthetic peptide compared to the originals. This allows them to strengthen the bonds in these peptides to ensure that they will remain intact in the bloodstream of the animal for as long as possible. Some peptides are also altered from their natural forms to attempt to alter how these chemicals will interact with the tissues. Much of the research on the side effects or reactions to these synthesized chemicals are still unknown, so researchers will need to take care to watch subjects closely to ensure they do not provide applications of peptides that are dangerous and alter the effects of their research.
- Another method used to protect the integrity of peptides for shipping is by shipping these chemicals in a freeze-dried state. This prevents any breakdown of the chemical for months or even years while they wait to be used, particularly if researchers keep these containers sealed or frozen. Researchers can then reconstitute small amounts of the peptide as necessary for individual applications to ensure that the chemicals are likely to behave consistently between trials. When ordering chemicals that require reconstituting, read the directions carefully to determine the concentration of the peptide. This will help to ensure that the chemicals are at the proper level and blended with the right liquid modifier to get accurate results without side effects.
- Companies that do not have ongoing trials for peptide research actively on their books are more likely to offer inexpensive peptides than those which are attempting to finish similar research products. Those that are currently performing trials on a given peptide will need to maintain a higher level of stock to ensure that they have enough to manage their own needs, so will likely sell any additional product they have on hand at a higher price to meet the demand. Comparing prices and maintaining a familiarity with others in the field can help to ensure that a fair price for peptides can be negotiated.
- Companies that produce peptides in mass quantities are also more likely to offer an affordable price. Not all companies are certified or capable of making consistent batches of peptides in large amounts, so it is important to carefully look into which peptide suppliers are the most appropriate for this task. Most who are capable of supplying large doses of peptides will note this in their name or description so that they can readily be identified. Consult with these companies regarding how much of a peptide it is appropriate to purchase at one time so that freshness can be guaranteed throughout the life of a trial.
- Investing in a company that promises quick shipping is also considered essential for those that are hoping to save money on investing in research grade peptides. The less time a peptide spends in transit, the longer it will last during the trial process, allowing scientists to perform additional trials for each round of an experiment without the worry that there will be inconsistency or negative side effects that could affect the level of research performed.
Like any product, it is vital for researchers to carefully compare companies before investing in peptides. To ensure consistency in research, scientists are often advised to invest in peptides from the same suppliers so they contain the same preservatives, require the same solutions for reconstitution and are designed to be constituted at the same level. Seeking out a company that is certified to create large batches of peptides and has years of experience can help to ensure that a research facility can continue to get the research products they require.
Some companies are willing to sign a long term contract with a research facility they know will be performing a research project for a long period of time. This helps to ensure that the company will continue to supply regular shipments with a set payment so that researchers do not have to worry that they will have the tools they need to manage their experiment.
Working out a long term contract helps to ensure consistency of product and shipments that is essential to accurate and reliable research. This provides an opportunity to perform multiple trials or mimic earlier experiments to help ensure that the results achieved are accurate and can be used as a benchmark for future assignments.