Discovery of novel peptide dendrimers with potent and broad spectrum of antimicrobial activity
ABSTRACT:Discovery of novel peptide dendrimers with potent and broad spectrum of antimicrobial activity
Thissa N. Siriwardena and Jean-Louis Reymond*
University of Bern
Multidrug resistant (MDR) Pseudomonas aeruginosa and Acinetobacter baumannii have been listed, together with Enterobacteriaceae, as the most critical human pathogens by the World Health More Organization in 2017. New antibiotics are urgently needed to address MDR bacteria. We recently reported antimicrobial peptide dendrimer (AMPD) G3KL, showing good activity against P. aeruginosa and other Gram-negative strains including MDR clinical isolates.1 We later optimized this dendrimer to a smaller lipidated analog, TNS18, which showed excellent activity against both gram negative and positive bacteria and was also active in a murine infection model against MDR clinical isolates of A. baumannii and E. coli.2 Here we report our latest progress in identifying new AMPD exploiting the concept of chemical space borrowed from small molecule cheminformatics and recently exemplified with bicyclic peptides.3 Our exploration of the dendrimer chemical space led us to the discovery of a more potent analogs of G3KL with an expanded activity range, improved serum stability and very good activity in an in vivo infection model.
1. Stach, M.; Siriwardena, T. N.; Kohler, T.; van Delden, C.; Darbre, T.; Reymond, J. L. Combining Topology and Sequence Design for the Discovery of Potent Antimicrobial Peptide Dendrimers against Multidrug-Resistant Pseudomonas Aeruginosa. Angew. Chem., Int. Ed. 2014, 53, 12827-12831.
2. Siriwardena, T. N.; Stach, M.; He, R.; Gan, B. H.; Javor, S.; Heitz, M.; Ma, L.; Cai, X.; Chen, P.; Wei, D.; Li, H.; Ma, J.; Kohler, T.; van Delden, C.; Darbre, T.; Reymond, J. L. Lipidated Peptide Dendrimers Killing Multidrug-Resistant Bacteria. J. Am. Chem. Soc. 2018, 140, 423-432.
3. Di Bonaventura, I.; Jin, X.; Visini, R.; Probst, D.; Javor, S.; Gan, B.-H. ; Michaud, G.; Natalello, A.; Doglia, S. M.; Kohler, T.; van Delden, C. ; Stocker, A.; Darbre, T.; Reymond, J.-L.; Chem. Sci. 2017, 8, 6784-6798.
Poster ID# 2973
Brain Penetrating IgG Fusion Proteins: from Genetic Engineering to Clinical Trials in Lysosomal Storage Disorders
ABSTRACT:Protein therapeutics can be re-engineer as brain penetrating IgG-fusion proteins for the CNS treatment of rare disorders, like Lysosomal Storage Disorders (LSD). Lysosomal enzymes, such as iduronase (IDUA) and sulfatases, are large molecule drugs that do not cross the blood-brain barrier (BBB). The BBB-penetration of enzyme therapeutics is enabled More by re-engineering the recombinant enzyme as bi-functional IgG fusion proteins, wherein the IgG domain targets a specific endogenous receptor-mediated transporter system within the BBB, such as the human insulin receptor (HIR). The enzyme therapeutic domain of the fusion protein exerts the pharmacological effect in brain once across the BBB. Several brain penetrating IgG-fusion proteins have been engineered and validated. First in human proof of concept phase II clinical trial in LSD will be discussed.
Note that this is scheduled for oral presentation in the Scientific Session 2: Drug Delivery, Wednesday September 26, 2018, 9:30-12:30. Thanks
Poster ID# 3049
Mohd Shamoon Asmat
A nanoformulation of lipase with cellulose embodied polypyrrole functionalized graphene oxide nanocomposite as promising nanobiocatalyst: Green approach for flavour synthesis
ABSTRACT:Enzymatic biocatalysis has a vast reputation on an industrial scale. The major hindrance faced by enzymes is their denaturation under various conditions. This work was performed to describe the facile procedure of a novel nanobiocatalyst, nano cellulose fused polypyrrole/graphene oxide nanocomposite for the efficacious immobilization of lipase, a More versatile hydrolytic enzyme having potential applications in industries. The fabricated nanocomposite was characterized using Fourier transform infrared spectroscopy, differential thermal analysis, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and Candida rugosa lipase was immobilized onto nanocomposite through physical adsorption. The catalytic efficiency and operational stabilities of immobilized lipase were improved significantly compared to the free lipase. The reusability profile outcomes showed that the immobilized lipase formulation was an outstanding nanobiocatalyst as it retained 85% of its original catalytic activity after 10 cycles of application. The nanobiocatalyst was employed for the synthesis of the fruit flavour compound, ethyl acetoacetate. The immobilized lipase successfully synthesised flavour compound in solvent free media and n-hexane having 27.5% and 75.5% ester yields respectively. Moreover, these outcomes demonstrating graphene oxide modified carrier induced stabilization, amended solvent tolerance and operational stability of immobilized enzyme, will have quintessential influence on practical scale up of biotechnological industries.
Poster ID# 3236
The Evolution of Therapeutic Peptide Structures as it Relates to Analytical Challenges
ABSTRACT:The utilization of peptides as therapeutic agents has evolved over the past two decades. The earliest drugs revolved around native structures such as glucagon and insulin, which were limited by their poor ADME properties including instability, and rapid proteolytic cleavage. Developing longer acting peptides was initially attempted by More incorporation of unnatural amino acids to block metabolism. Significant advances have resulted in longer acting peptides employing modifications to increase protein binding or decrease renal clearance. These structural changes including conjugation of peptides with PEG, lipids, EXTEN, and FC-fusion, create unique analytical challenges. Analytical methods for native peptides were comparable to small molecule assays by mass spectrometry. The development of higher molecular wt. peptides and conjugate technology made intact analysis impractical. Digestion of peptides followed by detection of tryptic fragments became the main stream for analysis. Issues with this technique included monitoring peptide fragments not representative of active or intact peptide. With the advent of high resolution mass spectrometry in 2005, intact peptide analysis became possible, eliminating these uncertainties. In addition to instrumental challenges, traditional extraction techniques for high protein binding peptides such as protein precipitation, SPE and liquid/liquid suffer from low extraction efficacy. In most cases, immunoprecipitation is the only option to achieve detection limits of 1 ng/ml or lower. Recent developments in extracting peptides with high protein binding have allowed improved detection levels without the need for expensive immunoprecipitation reagents. In summary, this talk will outline the evolution of therapeutic peptide structure as it relates to analytical challenges.
Poster ID# 3271
Engineered biosynthesis of β-branched tryptophan analogs
ABSTRACT:Non-canonical amino acids (ncAAs) with dual stereocenters at the α and β positions are valuable precursors to natural products and therapeutics. Despite their bioactive potential, applications of β-branched ncAAs are limited by their availability: synthesis requires multi-step routes that often exhibit low overall stereoselectivity. Enzymes use More simple materials and offer an efficient and sustainable alternative to chemical synthesis. However, like traditional organic methodologies, the enzymatic synthesis of β-branched ncAAs is often confounded by the presence of a second stereocenter. We previously engineered the β-subunit of the PLP-dependent enzyme tryptophan synthase from Pyrococcus furiosus (PfTrpB) as a stand-alone ncAA synthase able to generate tryptophan analogs from serine or threonine and the corresponding substituted indole. However, the enzyme’s yield and substrate scope were limited by competing hydrolysis of the reactive amino-acrylate intermediate.
The ideal synthase would need to utilize diverse indole and amino acid analogs to produce an array of β-branched ncAAs, making these desirable molecules readily available for the first time. Here we report such an engineered catalyst, PfTrpB7E6, that integrates nine mutations from mechanism-guided engineering, random mutagenesis, and recombination. We demonstrate the utility of PfTrpB7E6 as an ncAA synthase by producing 27 β-branched tryptophan analogs. The molecular basis for the efficient catalysis and versatile substrate scope was explored through X-ray crystallography and UV-visible light spectroscopy, which revealed that a combination of active-site and remote mutations increases the abundance and persistence of a key reactive intermediate. This enzyme provides a simple and environmentally benign platform for preparation of β-branched tryptophans.
Poster ID# 3394
Fernando De Leon
PNA-Peptide Hybrids as Potential miRNA Mimics
ABSTRACT:The level of complexity within the network of interactions and correlative regulation of microRNAs (miRNA) and RNA-binding proteins (RBP) and their role in cancer has sparked new-found interest within the scientific community to study and target this process in modern cancer therapies. The post-transcriptional mechanisms mediated by RBPs and miRNAs More and their role as key regulators in cancer make these types of proteins and molecules interesting targets for gene expression regulation and cancer therapy. Synthetic PNA-peptide hybrid molecules are novel hybrid molecules that have the potential to behave as synthetic miRNA mimics imitating the regulatory processes their natural counterparts take part in. From a chemical perspective and structurally speaking, PNA (peptide nucleic acid)-peptide hybrid molecules differ only slightly from natural miRNAs. Various synthetic approaches have been applied in the synthesis of PNA-peptide hybrids to imitate the natural miRNA structure such as the addition of charge on the back bone of the PNA component through use of γ-substituted PNA monomers. Cyclization of these types of molecules is also possible through our synthetic methods giving rise to various secondary structures. Binding assay experiments and preliminary data have demonstrated high binding affinity of these hybrids molecules to RBPs. Functional interactions between various known miRNAs and RBPs can thus be manipulated through the implementation and design of sequence specific PNA-peptide hybrid molecules. Sequencing technology and previous research efforts have contributed to extensive databases of the nucleotide sequences and structures of thousands of miRNAs and RBPs. This information provides the accessibility and possibility of designing and synthesizing PNA-peptide hybrid molecules to mimic or interact with a specific miRNA or RBP of interest.
Poster ID# 3403
Using polyethylene glycol to increase peptide conformational stability by exploiting noncovalent interactions
ABSTRACT:Polyethylene glycol (PEG) has been used for over 30 years to increase the serum half-life of protein drugs. Despite its wide use, the mechanism of conformational stabilization for PEG has remained elusive. In this work we present a model for PEG based conformational stabilization based on noncovalent interactions. We have sown that PEG can increase More the stability of salt bridges, hydrogen bonds and nonpolar interactions. We aim to use PEG to exploit noncovalent interactions to be able to predict PEG-based stabilization.
Poster ID# 3458
Stapling of two asparagine-linked O-allyl PEG oligomers increases the conformational stability of the WW domain
ABSTRACT:Hydrocarbon stapling and PEGylation are distinct strategies for enhancing the conformational stability and/or pharmacokinetic properties of peptide and protein drugs. Here we combine these approaches by incorporating asparagine-linked O-allyl PEG oligomers at two positions within the β-sheet pro-tein WW, followed by stapling of the PEGs via ole-fin More metathesis. The impact of stapling two sites that are close in primary sequence is small relative to the impact of PEGylation alone and depends strongly on PEG length. In contrast, stapling of two PEGs that are far apart in primary sequence but close in tertiary structure provides substantially more stabi-lization, derived mostly from an entropic effect. Comparison of PEGylation + stapling vs. hydrocar-bon modification + stapling at the same positions in WW reveals that both approaches provide similar overall levels of conformational stability.
Poster ID# 3460
The use of an agarose-based ion-exchange resin in the purification of a 45-amino acid residue peptide
ABSTRACT:Increased lifetime of RPC resins in insulin production by clean-up using WorkBeads 40S
Purification of recombinant insulin requires very high purity, often achieved by high-resolution reversed phase chromatography (RPC) based on silica. Impurities from the feed often cause fouling of the silica resins that is difficult to remove since the option of More cleaning-in-place using sodium hydroxide is limited. These issues result in shortened lifetime of the RPC columns. We present here that an introduction of an ion exchange chromatography step before RPC removes the bulk of impurities from the feed which significantly will increase the lifetime of the RPC column.
By introducing a capture step, using WorkBeads™ 40S (a cation exchanger), a standard purification process involving a combination of two RPC steps with two different buffer systems (to obtain complementary selectivity) was improved.
WorkBeads 40S is an agarose based resin with sulfonate ligands which is stable in high concentration of sodium hydroxide thus allowing efficient cleaning-in-place. A feed containing 72.5% pure human insulin precursor (Met-Lys-Human insulin) was applied to the WorkBeads 40S column, followed by the two RPC steps. Each step was optimized to give a yield of 90% while maximizing the purity after each step. The amount of impurities in the applied feed on the first RPC column could be reduced from 27.5% to 12%. This improvement significantly reduces the fouling of the first RPC column and prolongs its lifetime. The final purity for the human insulin precursor was > 99%. A comparison was also done using Capto™ SP ImpRes cation exchange resin in the capture step which resulted in a less pure target protein compared to using WorkBeads 40S.
Poster ID# 3531
Efforts toward understanding peptide permeability
ABSTRACT:Measuring cell permeability of peptides is critical for understanding and optimizing activity of ligands with intracellular targets and assessing potential for oral bioavailability. While small molecule permeability has been extensively studied, methods for assessing peptide permeability are often lower throughput, target-specific, or less robust. More Herein we describe the Nanoclick assay, a high-throughput and target agnostic approach for assessing the permeability of azide-containing peptides. We present comparisons of Nanoclick and cell-based on-target activity, and cell-free reactivity data used to better understand cycloaddition kinetics.
Poster ID# 3534
Discovery of Stable Chemerin Analogs Selective for CMKLR1
ABSTRACT:Yan Wang a, Yvonne Angell a, Yun Wu b, Yanfen Teng b, Meng Li b, Krishna Kodukula c and Robert Drakas c
a. Department of Peptide Chemistry, ChemPartner SSF;
b. ChemPartner Shanghai;
c. ShangPharma Innovation, 280 Utah Avenue, Suite 250, SSF, CA 94080
Chemerin is an immunomodulating factor secreted in many tissues including the spleen, lymph More nodes, adipose tissue and epithelia. It was identified as a ligand of the Chemerin receptor (ChemR23 / CMKLR1), a chemokine like G protein-coupled receptor (GPCR) and induces chemotaxis in natural killer cells, macrophages, and immature dendritic cells. It is secreted as an inactive precursor, pro-chemerin, and is activated by proteolytic removal of amino acids from the c-terminus by proteases such as elastase, cathepsin G, or kallikrein 7. The nonapeptide, chemerin-9, derived from the C-terminus of the processed form of chemerin is also a potent agonist of CMKLR1.
Chemerin is involved in a variety of functions including cell differentiation and has been linked with diverse indications such as inflammation, psoriasis and obesity. However, its mechanism and detailed signaling pathway remain unclear. Also, chemerin and chemerin-9 are rapidly degraded and inactivated in plasma, which has limited their use in in vivo experiments and as potential therapies. There is a need to develop stable and selective molecular tools to accelerate pharmacological analysis of Chemerin–CMKLR1 interactions, better define signaling pathways, and screen in vivo to validate CMKLR1 as a potential therapeutic target.
We carried out multiple peptide modification strategies and tested more than 230 peptides in an SAR study, using human CMKLR1 over-expressed in U2OS cells as our primary assay. A number of potent analogs were identified, among them, two peptides were chosen as lead candidates for further studies. Both analogs showed good metabolic stability and no toxicity. They also had excellent GPCR selectivity during GPCR panel screening at 10 µM concentration.
Thus, these analogs have emerged as useful tools for further interrogation of chemerin’s biological role and as potential lead structures for continued development.
Poster ID# 3613
Early Development of a KISS1/GPR54 Receptor Agonist for Prostate Cancer
ABSTRACT:Early Development of a KISS1/GPR54 Receptor Agonist for Prostate Cancer
Yvonne Angella, Yan Wanga, Yun Wub, Wen Jieb, Chen Haixia b, Yanfen Tengb,
Meng Xiangminb, Krishna Kodukulac, and Robert Drakasc
aDepartment of Peptide Chemistry, ChemPartner SSF
bDepartment of Peptide Chemistry, ChemPartner Shanghai
cShangPharma Innovation, 280 Utah Avenue, More Suite 250, SSF, CA 94080
Metastin/kisspeptin is a C-terminal amidated peptide of 54 amino acid residues in length isolated from human placental tissue. It is a ligand of the orphan G-protein-coupled receptor KISS1R, also called GPR54, which is expressed throughout the central nervous system and in a variety of endocrine and gonadal tissues. Kisspeptin plays a pivotal role in controlling gonadotropin-releasing hormone (GnRH) neurons. Kisspeptin acts directly on the GnRH neurons to stimulate GnRH release.1 Compared to the full-length metastin protein, the N-terminally truncated peptide metastin(45–54) has 3–10 times higher receptor affinity and enhanced ability to increase intracellular calcium concentration, which is essential for activation of protein kinases involved in intracellular signaling in a number of pathways that affect reproduction and cell migration.2 KISS1R receptor agonists and antagonists have been explored to investigate the biology of targeting the KISS1 receptor. Metastin(45–54) analogues with higher agonist activity and improved metabolic stability have been reported in the literature, and shown to suppress plasma testosterone in male rats with continuous subcutaneous administration.3 Several KISS1R agonists have reached phase II in the clinic.4
Continuous subcutaneous administration of KISS1R agonists has been shown to induce a transient increase in plasma testosterone, followed by abrupt reduction of plasma testosterone to castrate levels within 3–7 days, which can be sustained throughout a 4-week dosing period. These suppressive effects are more rapid and profound than those induced by the GnRH agonist analog leuprolide.3 Hormonal therapy involving luteinizing hormone (LH)-releasing hormone agonists (LHRHs) is a widely used systemic treatment for prostate cancer and is recommended in the European Association of Urology guidelines on prostate cancer for use in patients with locally advanced and metastatic disease.5 We sought to design novel peptides with increased activity against KISS1R along with significantly enhanced plasma stability over previously reported KISS1R agonist compounds, and demonstrate in vivo efficacy of these novel peptides. The peptides were rationally designed based on Ala scanning and known SAR, and screened in vitro in a GPR54-NFAT-bla CHO-K1 cell-based primary assay, as well as a cell migration secondary assay used to test the peptides’ effect on migratory properties of cells stably expressing human KISS1R. Lead peptides selected from the in vitro results were screened for plasma stability and in vivo efficacy. The lead peptide, YA-156, demonstrated potent in vitro as well as in vivo efficacy in a subcutaneous, xenograft x1LnCAP BALB/c nude mouse prostate cancer model, excellent plasma stability, and a good in vitro ADME profile, aside from some unexpected receptor selectivity results.
Further studies are currently in progress to assess the in vivo effects of these novel KISS1R analogs. Chronic administration of kisspeptin analogs via a sustained release formulation may hold promise of a novel therapeutic approach for suppressing reproductive functions and hormone-related diseases, such as prostate cancer.
1. Kotani, M. et al., J. Biol. Chem., 2001, 276(37), 34631–34636.
2. Ohtaki, T. et al., Nature, 2001, 411, 613.
3. Matsui, H. et al., Eur. J. Pharmacol., 2014, 735, 77–85.
4. MacLean, D.B. et al., J. Clin. Endocrinol Metab., 2014, 99(8), E1445–E1453.
5. EAU Guidelines on prostate cancer, 2007, www.uroweb.org.
Poster ID# 3622
Controllable Core–Shell-Type Resin for Solid-Phase Peptide Synthesis
ABSTRACT:Since Merrifield has developed solid-phase peptide synthesis (SPPS) method, polystyrene (PS) based resins have been utilized mostly in peptide synthesis. For efficient SPPS, we have developed several kinds of core-shell type resins, in which reactive functional groups are mainly located on the shell layer of the resins.The core-shell (CS) structure More was designed to overcome the diffusion problem and for easy accessibility of reagents, and washings. Because of this distinctive structural feature, the CS type resins afforded high performance in peptide synthesis and even photolytic cleavage reactions.
These resins were prepared by suspension co-polymerization, two-step polymerization, cross-linking core backbone, partial hydrolysis, and biphasic functionalization methods. Recently, we have developed diffusion-controlled functionalization method to obtain CS type PEGylated PS resin. To evaluate the performance of the resins, various peptide sequences were synthesized, and the results were compared with those of non-CS type PS resin and other PEG-based resins. Those resins gave excellent performance in peptide synthesis as well as screening peptide ligands form peptide libraries. When properly designed, the PEGylated resin could also be used for the synthesis of oligonucleotide, and purification of therapeutic antibodies.
 Kim, H.; Cho, J. K.; Chung, W. J.; Lee, Y. S. Org. Lett. 2004, 6, 3273.  Lee, T. K.; Ryoo, S. J.; Byun, J. W.; Lee, S. M.; Lee, Y. S. J. Comb. Chem. 2005, 7, 170.  Lee, T. K.; Lee, S. M.; Ryoo, S. J.; Byun, J. W.; Lee, Y. S. Tetrahedron Lett. 2005, 46, 7135.
 Cho, H. J.; Lee, T. K.; Kim, J. W.; Lee, S. M.; Lee, Y. S. J. Org. Chem. 2012, 77, 9156.  Kim, J; Kim S.; Shin, D.S.; Lee, Y.S. J. Peptide Science, 2018, 24:e3061.
Poster ID# 3629
Leveraging the Knorr Pyrazole Synthesis for the Facile Generation of Thioester Surrogates for use in Native Chemical Ligation
ABSTRACT:Facile synthesis of C‐terminal thioesters is integral to native chemical ligation (NCL) strategies for chemical protein synthesis. We introduce a new method of mild peptide activation, which leverages solid‐phase peptide synthesis (SPPS) on an established resin linker and classical heterocyclic chemistry to convert C‐terminal peptide hydrazides More into their corresponding thioesters via an acyl pyrazole intermediate. Peptide hydrazides, synthesized on established trityl chloride resins, can be activated in solution with stoichiometric acetyl acetone (acac), readily proceed to the peptide acyl pyrazoles. Acyl pyrazoles are mild acylating agents and are efficiently exchanged with an aryl thiol, which can then be directly utilized in NCL. The mild, chemoselective, and stoichiometric activating conditions allow this method to be utilized through multiple sequential ligations without intermediate purification steps.
Poster ID# 3670
cGMP Peptide Production from mg to kg with Automation and Microwave Assisted Heating
ABSTRACT:Peptides are ideal drug candidates due to their inherent high potency, low toxicity, and their ability to effect a broad range of targets . With several high revenue peptide drugs on the market and a full pipeline of potential candidates , the demand for a highly robust and effective synthetic method is of great importance .
Currently, More peptide synthesis research and production both face similar challenges – a sluggish and wasteful workflow in desperate need for optimization. The typical conventional optimization steps usually take a shotgun approach: screen resins, screen different reagent excesses, screen activators, etc. This synthetic process necessitates tens or hundreds of reactions, all of which can often take weeks or months to complete while requiring a great deal of time, money, and resources.
To address the needs of the market, new cGMP methodology has been developed utilizing automation and microwave assisted heating. This work details mechanistic-based, innovative improvements to the chemical methodology of solid phase peptide synthesis, application of these improvements to high-throughput SPPS for personalized medicine via peptide vaccines [4,5] and large scale peptide production with cGMP considerations.
 D. J. Craik, D. P. Fairlie, S. Liras, D. Price. Chem Biol Drug Des, 2013, 81, 136.
 K. Fosgerau, T. Hoffman. Drug Discov Today, 2015, 20, 122.
 J. M. Collins, K. A. Porter, S. K. Singh, G. S. Vanier. Org. Lett. 2014, 16, 940.
 P. A. Ott et al. Nature, 2017, 547, 217.
 R. Takahashi et al. Breast Cancer Research, 2014,16, R70.
Poster ID# 3689
Pushing the boundaries of solid phase peptide synthesis in the manufacture of complex research tools
ABSTRACT:Peptide-based research tools are a valuable asset in performing basic biological research. The availability of for consistent, high quality reagents is a vital element in the researcher’s toolbox in order to study areas such as receptor binding, and cell biology.
Total chemical synthesis offers the researcher a high degree of control in the design More of standard and bespoke peptide-based research tools. The nature of solid phase peptide synthesis (SPPS) allows the incorporation of natural or unnatural modifications in a highly specific manner leading to reproducible manufacturing methods and product quality. Historically, SPPS methods limited the length of peptides that could be produced chemically to 40-60 amino acids, but modern methods have now pushed the boundary beyond 100 amino acids enabling small proteins to become legitimate targets for synthesis.
Almac has developed methods in SPPS in the development of relevant peptide / small protein targets such as chemokines (70-80 amino acids), ubiquitin reagents (76 amino acids), and histones (ca. 135 amino acids). Historically, recombinant methods of production have been able to cope with the sheer length of the sequences, but been nor been able to control the introduction of site-specific modifications, such as fluorophores, or post-translational modifications such as methylations or phosphorylations. Almac has perfected methods of synthesis of such challenging molecules to produce physiologically relevant reagents that previously were not obtainable.
In this paper, we describe the synthetic methods employed towards a range of highly complex protein-based research tools, and the advantages they bring to the research community.
Poster ID# 3699
Stationary Phases for the Process Scale Purification of Peptides and Insulin Analogs
ABSTRACT:The purification process of crude synthetic peptides as well as recombinant Insulin typically includes a reversed phase high performance liquid chromatography (HPLC) step. A single step process is most desired but a multiple step process is often necessary to achieve purity greater than 98% especially with long peptide and recombinant proteins More like human Insulin. When a multistep process is used, the first steps are designed to remove most of the undesired components whereas the last step is developed to further “polish” the API to the desired purity level.
This presentation will cover the current state of the art for large scale preparative HPLC purification of synthetic peptide. The chemical and physical property of the purification packing material will be discussed as well as the mobile phase and critical process parameter needed to develop robust and scalable process. A revolutionary hybrid silica based stationary phase designed for the purification of peptide/proteins prone to aggregation will be highlighted and several purification case studies such as GLP-1 analogues and Insulin analogues will be presented.
Poster ID# 3703
Targeted Alpha-particle Therapy for Metastatic Uveal Melanoma
ABSTRACT:New effective therapies are greatly needed for metastatic uveal melanoma, the most common ocular malignancy, which has a very poor prognosis with a median survival of <1 year. The melanocortin 1 receptor (MC1R) is expressed in 94% of uveal melanoma. MC1R is not expressed in normal tissues of concern for toxicity. We have previously reported a More MC1R specific ligand (MC1RL) with high affinity and selectivity for MC1R. Ac-225 is a therapeutic radionuclide that emits 4 alpha particles in the decay chain. The aim of this study is to use MC1RL as a targeting scaffold for development of a radiopharmaceutical by conjugation of Ac-225 chelate.