solvent comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-03-30. Where a claim depends on a specific study, the study is described rather than over-claimed.
Solvent choice depends on the peptide's sequence, charge, and solubility profile. Sterile water is common for freely soluble peptides, while aqueous buffers or dilute acid or base may be needed for others. Some sequences contain hydrophobic regions that resist water alone and require a small amount of organic co-solvent. The solvent's pH can affect charge state, aggregation, and stability. Because peptides vary widely, no single universal reconstitution liquid exists, and suppliers often provide a recommended solvent based on testing of a specific lot or sequence.
After a solvent is added, the vial is typically swirled or gently inverted rather than shaken vigorously. Shaking can introduce air and shear forces that promote foaming or aggregation, especially for longer peptides. Dissolution may take several minutes, and the solution should become clear unless the peptide is intentionally in suspension. Concentration is calculated from the mass of peptide stated on the vial label divided by the total liquid volume. If the dried peptide contains salts or counterions, the actual peptide content may be lower than the nominal mass.
Reconstitution concentration is chosen from the mass of peptide and the volume of solvent added. Researchers often prepare a concentrated stock and then divide it into single-use aliquots to reduce freeze-thaw cycling. The actual peptide content may differ from label mass because of counterions, water, or impurities. For that reason, quantitative work may require independent measurement such as amino acid analysis or ultraviolet absorbance. Records of solvent, volume, date, and lot help trace later observations.
Lyophilized peptides are supplied as dry powders or porous cakes that remain stable during shipment and short-term storage. Reconstitution is the laboratory step of adding a suitable solvent so the solid dissolves into a liquid stock. The dried state limits hydrolysis and microbial growth, but it does not remove all residual water or salts. Sequence, counterion, and manufacturing method influence how quickly and completely a peptide enters solution. Researchers treat reconstitution as a practical starting point for later dilution, analysis, or assay work.
Solvent choice depends on peptide polarity and intended use. Many peptides dissolve in water or buffered aqueous solutions, while hydrophobic sequences may need a small amount of organic solvent such as acetonitrile or dimethyl sulfoxide before aqueous dilution. The solvent should match the downstream analytical method and not interfere with detection. Gentle mixing or brief sonication can help, but vigorous agitation may promote foaming or aggregation. Complete dissolution is judged by a clear liquid free of visible particles, though some turbidity can persist.
| Property | Value | Notes |
|---|---|---|
| Physical state before solvent | Lyophilized powder or cake | Freeze-drying removes water under vacuum and leaves a porous solid. |
| Common reconstitution liquid | Sterile water or aqueous buffer | Compatibility depends on peptide sequence, charge, and pH requirements. |
| Typical solution pH | pH 3 to 7 | Acidic or slightly acidic conditions are common; some peptides need other ranges. |
| Appearance after dissolution | Clear to slightly opalescent solution | Cloudiness can indicate incomplete dissolution, aggregation, or undissolved excipients. |
| Concentration basis | Mass of peptide per volume of solvent | Label mass may include counterions or salts, so peptide content can differ. |
During reconstitution, solvent penetrates the dry cake and breaks intermolecular contacts that held the peptide in solid form. Dissolution occurs as individual peptide molecules become surrounded by solvent. Hydrophobic regions can associate with one another instead of dissolving, which may produce turbidity or aggregates. pH and ionic strength influence the charge state of ionizable groups and therefore solubility. Buffer salts can help maintain a stable pH, but they can also participate in interactions that affect the final solution.
The concentration of a reconstituted peptide is calculated from the mass of peptide powder and the volume of solvent added. This calculation assumes the powder contains only peptide, but many preparations include counterions, water, or salts. Analytical methods such as ultraviolet absorbance or amino acid analysis can estimate actual peptide content. The relationship between nominal and actual concentration is an area where measurements matter. Open questions remain about how aggregation changes the effective concentration in solution.
Peptide reconstitution is the process of dissolving a dried peptide preparation in a liquid solvent to form a solution. Many peptides are supplied as lyophilized powders because removing water improves stability during shipping and storage. The dried material may appear as a cake, flake, or loose powder depending on the manufacturing and drying method. Reconstitution restores the peptide to a liquid state so that it can be further diluted, analyzed, or handled in laboratory workflows. The term is distinct from dilution, which lowers concentration after a solution already exists.
The choice of solvent depends on the peptide's sequence, charge, and solubility profile. Water is common for hydrophilic peptides, while aqueous mixtures containing acetonitrile, methanol, or a small amount of acid may be needed for hydrophobic or basic sequences. Adding the liquid to the powder, rather than the reverse, can reduce clumping and improve wetting. Gentle mixing or brief vortexing may help, but vigorous agitation can create foam and shear sensitive structures. Complete dissolution is judged by a clear solution with no visible particles.
RCO2H + R'2NH → RCO−2 + R'2NH+2 RCO−2 + R'2NH+2 → RC(O)NR'2 + H2O Esters are far superior substrates relative to carboxylic acids. Further "activating" both acid chlorides (Schotten-Baumann reaction) and anhydrides (Lumière–Barbier method) react with amines to give amides: RCO2R" + R'2NH → RC(O)NR'2 + R"OH RCOCl + 2R'2NH → RC(O)NR'2 + R'2NH+2Cl− (RCO)2O + R'2NH → RC(O)NR'2 + RCO2H Peptide synthesis use coupling agents such as HATU, HOBt, or PyBOP. The hydrolysis of nitriles is conducted on an industrial scale to produce fatty amides. Laboratory procedures are also available. Many specialized methods also yield amides. A variety of reagents, e.g. tris(2,2,2-trifluoroethyl) borate have been developed for specialized applications. Amidogen Amino radical Imidic acid Metal amides IUPAC Compendium of Chemical Terminology
People with Aarskog–Scott syndrome often have distinctive facial features, such as widely spaced eyes (hypertelorism), a small nose, a long area between the nose and mouth (philtrum), and a widow's peak hairline. They frequently have mild to moderate short stature during childhood, but their growth usually catches up with that of their peers during puberty. Hand abnormalities are common in this syndrome and include short fingers (brachydactyly), curved pinky fingers (fifth finger clinodactyly), webbing of the skin between some fingers (cutaneous syndactyly), and a single crease across the palm. Other abnormalities in people with Aarskog–Scott syndrome include heart defects and a split in the upper lip (cleft lip) with or without an opening in the roof of the mouth (cleft palate). Most males with Aarskog–Scott syndrome have a shawl scrotum, in which the scrotum surrounds the penis instead of hanging below. Less often, they have undescended testes (cryptorchidism) or a soft out-pouching around the belly-button (umbilical hernia) or in the lower abdomen (inguinal hernia). The intellectual development of people with Aarskog–Scott syndrome varies widely. Some may have mild learning and behavior problems, while others have normal intelligence. In rare cases, severe intellectual disability has been reported.
The histology of ALK-negative ALCL, similar to ALK-positive ALCL, consist of "hallmark" cells that strongly express CD30. Unlike ALK-positive ALCL, however, ALK-negative ALC does not fall into different morphological patterns. The histological of this disease may overlap with and be difficult to distinguish from other CD30-positive T-cell lymphomas or the nodular sclerosis form of Hodgkin lymphoma. Cases in which ALK-negative ALCL is not distinguishable from the latter lymphomas are best diagnosed as peripheral T-cell lymphoma not otherwise specified (PTL, NOS). The histology of ALK-negative ALCL may also overlap with tumors of non–T-cell lineage such as various carcinomas. The differential diagnoses of ambiguous cases may be helped by examining the tumor cells for the expression of certain marker proteins. For example, expression of CD56, MUC1 (also termed EMA for epithelial membrane antigen), and clusterin and strong uniform expression of CD30 support the diagnosis of ALK-negative ALCL over PTL, NOS, while variable CD30 expression and extensive expression of T-cell receptor proteins favor PTCL-NOS over ALK-negative ALCL. Detection of certain gene abnormalities (see next section) may also help distinguishing these diseases.
The first class of adenylyl cyclases occur in many bacteria including E. coli (as CyaA P00936 [unrelated to the Class II enzyme]). This was the first class of AC to be characterized. It was observed that E. coli deprived of glucose produce cAMP that serves as an internal signal to activate expression of genes for importing and metabolizing other sugars. cAMP exerts this effect by binding the transcription factor CRP, also known as CAP. Class I AC's are large cytosolic enzymes (~100 kDa) with a large regulatory domain (~50 kDa) that indirectly senses glucose levels. As of 2012, no crystal structure is available for class I AC. Some indirect structural information is available for this class. It is known that the N-terminal half is the catalytic portion, and that it requires two Mg2+ ions. S103, S113, D114, D116 and W118 are the five absolutely essential residues. The class I catalytic domain (Pfam PF12633) belongs to the same superfamily (Pfam CL0260) as the palm domain of DNA polymerase beta (Pfam PF18765). Aligning its sequence onto the structure onto a related archaeal CCA tRNA nucleotidyltransferase (PDB: 1R89) allows for assignment of the residues to specific functions: γ-phosphate binding, structural stabilization, DxD motif for metal ion binding, and finally ribose binding.
The Bergmann degradation makes use of the azide degradation described by the Curtius rearrangement. Curtius also attempted to degrade benzoylated amino acids; however, his method involved splitting the carbamate with strongly energetic treatment with acids, which lead to decomposition of the resultant aldehyde and acid amides. This convinced Bergmann that Curtius' azide degradation could be followed by treatment with benzyl alcohol (his carbobenzoxy method) to isolate the resultant amino acid aldehyde and residual peptide amide for sequencing purposes.
Sources: en.wikipedia.org
Activity-based proteomics, or activity-based protein profiling (ABPP) is a chemoproteomic strategy that employs modular probes to directly assess the functional state of enzymes within complex proteomes. Unlike expression-based proteomics, which measures protein abundance, ABPP provides information about catalytic activity, thereby enabling researchers to distinguish between active and inactive forms of enzymes. This functional perspective has proven valuable for identifying drug targets, mapping ligandable sites, and understanding enzyme regulation in physiological and pathological contexts. By covalently modifying active sites, activity-based probes (ABPs) allow selective tagging, enrichment, and isolation of proteins, reducing the complexity of proteomic samples and facilitating downstream analysis. ABPP has been applied across diverse biological systems, including cells, tissues, and whole organisms, and has contributed to advances in biomarker discovery, drug development, and in vivo imaging.
Alpha-synuclein primary structure is usually divided in three distinct domains: Residues 1-60: An amphipathic N-terminal region dominated by four 11-residue repeats including the consensus sequence KTKEGV. This sequence has a structural alpha helix propensity similar to apolipoproteins-binding domains. It is a highly conserved terminal that interacts with acidic lipid membranes, and all the discovered point mutations of the SNCA gene are located within this terminal. Residues 61-95: A central hydrophobic region which includes the non-amyloid-β component (NAC) region, involved in protein aggregation. This domain is unique to alpha-synuclein among the synuclein family. Residues 96-140: a highly acidic and proline-rich region which has no distinct structural propensity. This domain plays an important role in the function, solubility and interaction of alpha-synuclein with other proteins.
In 2004, development of an antisense therapy for spinal muscular atrophy began. Over the following years, an antisense oligonucleotide later named nusinersen was developed by Ionis Pharmaceuticals under a licensing agreement with Biogen. In December 2016, nusinersen received regulatory approval from FDA and soon after, from other regulatory agencies worldwide. As of 2020, more than 50 antisense oligonucleotides were in clinical trials, including over 25 in advanced clinical trials (phase II or III). A follow-on drug to Inotersen is being developed by Ionis Pharmaceuticals and under license to Akcea Therapeutics for hereditary transthyretin-mediated amyloidosis. In this formulation the ASO is conjugated to N-Acetylgalactosamine enabling hepatocyte-specific delivery, greatly reducing dose requirements and side effect profile while increasing the level of transthyretin reduction in patients.
ADAM (A Database of Anti-Microbial peptides) Archived 2015-06-17 at the Wayback Machine at ntou.edu.tw AntiFP Prediction of antifungal peptides AntiMPmod Prediction of antimicrobial potential of modified peptides Antimicrobial+Cationic+Peptides at the U.S. National Library of Medicine Medical Subject Headings (MeSH) AntiTbPred Prediction of anti-tuberculosis peptides Antimicrobial Peptide Database Archived 2011-07-20 at the Wayback Machine at University of Nebraska Medical Center Antimicrobial Peptide Scanner Deep Learning based AMP prediction server AntiTbPdb Anti Tubercular Peptide Database BioPD[link removed] at Peking University Health Science Center CAMP:Collection of Anti-Microbial Peptides at National Institute for Research in Reproductive Health (NIRRH) DBAASP - Database of Antimicrobial Activity and Structure of Peptides] LAMP at Fudan University PeptideLocator Prediction of functional peptides, including antimicrobial peptides, in a protein sequence PeptideRanker Bioactive peptide, including antimicrobial peptide, prediction modlAMP Python package for computational work with antimicrobial peptides, including sequence handling, -design, -prediction, descriptor calculation and plotting
Sources: en.wikipedia.org
Amyloid beta can be measured semiquantitatively with immunostaining, which also allows one to determine location. Amyloid beta may be primarily vascular, as in cerebral amyloid angiopathy, or in amyloid plaques in white matter. One sensitive method is ELISA which is an immunosorbent assay which utilizes a pair of antibodies that recognize amyloid beta. Atomic force microscopy, which can visualize nanoscale molecular surfaces, can be used to determine the aggregation state of amyloid beta in vitro. Vibrational microspectroscopy is a label-free method that measures the vibration of molecules in tissue samples. Amyloid proteins like Aβ can be detected with this technique because of their high content of β-sheet structures. Dual polarisation interferometry is an optical technique which can measure early stages of aggregation by measuring the molecular size and densities as the fibrils elongate. These aggregate processes can also be studied on lipid bilayer constructs. TPM21 Sylvain Lesné – Aβ*56 Online Mendelian Inheritance in Man (OMIM): 104300
In an experiment described in the 2016 paper, rhesus macaques were infected with Ebola virus and treated with a combination of ansuvimab and another antibody isolated from the same subject, mAb100. Three doses of the combination were given once a day starting 1 day after the animals were infected. The control animal died and the treated animals all survived. In a second experiment described in the 2016 paper, rhesus macaques were infected with Ebola virus and only treated with ansuvimab. Three doses of ansuvimab were given once a day starting 1 day or 5 days after the animals were infected. The control animals died and the treated animals all survived. Unpublished data referred to in a publication of the 2018 Phase I clinical trial results of ansuvimab, reported that a single infusion of ansuvimab provided full protection of rhesus macaques and was the basis of the dosing used for human studies.
Effective on new passenger cars sold in the United States after January 1, 1964. front outboard lap belts were required. On September 9, 1966, the National Traffic and Motor Vehicle Safety Act became law in the U.S., the first mandatory federal safety standards for motor vehicles. Effective in 1966, US-market passenger cars were required to be equipped with padded instrument panels, front and rear outboard lap belts, and white reverse (backup) lamps. In 1966, the U.S. established the United States Department of Transportation (DOT) with automobile safety as one of its purposes. The National Transportation Safety Board (NTSB) was created as an independent organization on April 1, 1967, but was reliant on the DOT for administration and funding. However, in 1975 the organization was made completely independent by the Independent Safety Board Act (in P.L. 93-633; 49 U.S.C. 1901). In 1967, equipment specifications by such major fleet purchasers as the City and County of Los Angeles, California, encouraged the voluntary installation in most new cars sold in the US of safety devices, systems, and design features including:
Sources: en.wikipedia.org
Reconstitution means adding a liquid to a dried peptide to form a solution. The dried material is usually a lyophilized powder or cake produced by freeze-drying. The resulting liquid is a stock solution that can be diluted or analyzed further.
Freeze-drying removes water and limits hydrolysis and oxidation during storage. The dried solid is generally more stable and easier to ship than a liquid. It also allows a defined amount of material to be sealed in a single vial.
No. Solubility depends on the amino acid sequence, charge, and hydrophobic content. Some peptides require buffer, dilute acid, dilute base, or a small amount of organic solvent. A supplier's recommended solvent is based on the specific peptide.
The solvent depends on peptide sequence and application. Water or aqueous buffer works for many hydrophilic peptides, while hydrophobic peptides may require a water-miscible organic solvent. The chosen solvent must be compatible with the assay or analytical instrument.