Basic procedures

1999 ◽  
Author(s):  
Weng C. Chan ◽  
Peter D. White
Keyword(s):  
Peptide Synthesis ◽  
Reaction Vessel ◽  
Inert Gas ◽  
Peptide Chain ◽  
Correct Method ◽  
Sintered Glass ◽  
The Subject ◽  
Gas Bubbling

A number of excellent descriptions of the techniques related to peptide chain assembly have already been published. These processes are also described in the operator manuals supplied by the peptide synthesis instrument manufacturers. Accordingly, the treatment of the subject presented here has been kept brief in order to provide more space in this volume for those topics not covered in detail in other publications of this type. The protocols have been written as they would be carried out using a manual peptide synthesis vessel. Whilst it is appreciated that most scientists preparing peptides will be using automated peptide synthesizers, it is not possible, given the wide variation in operating procedures, to describe how such methods may be applied to individual instruments. Particular emphasis has been given here to those operations which are typically carried out off-instrument, such as first residue attachment and peptide-resin cleavage. The operations described in this chapter can be carried out in a purpose-built peptide synthesis vessel or in a sintered glass funnel fitted with a three-way stopcock. The operation of the system is extremely simple: solvents are added from the top of the vessel, ensuring any resin adhering to the sides is rinsed down into the resin bed; the resin bed is agitated by setting the tap to position 1 to allow flow of nitrogen to the reaction vessel; solvents and reagents are removed by setting the tap to position 2 to connect the vessel to the vacuum. The use of such vessels has previously been described in detail. Peptide synthesis resins are extremely fragile and the beads, if wrongly handled, can easily fracture, leading to the generation of fines which can block reaction vessel filter-frits and solvent lines. It is particularly important that the correct method is used for mixing the resin and soluble reactants. Polystyrene-based supports are best agitated by bubbling an inert gas through the resin bed, or by shaking or vortexing the reaction vessel. Whilst all of these approaches are employed in commercial synthesizers, gas-bubbling and shaking are the most appropriate for use in manual synthesis.

Fmoc Solid Phase Peptide Synthesis

1999 ◽  
Keyword(s):  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Peptide Chain ◽  
Standard Approach ◽  
Side Chain ◽  
Complex Structures ◽  
Protein Conjugation ◽  
Chemoselective Ligation ◽  
Routine Production

In the years since the publication of Atherton and Sheppard's volume, the technique of Fmoc solid-phase peptide synthesis has matured considerably and is now the standard approach for the routine production of peptides. The basic problems outstanding at the time of publication of this earlier work have now been, for the most part, solved. As a result, innovators in the field have focussed their efforts to develop methodologies and chemistry for the synthesis of more complex structures. The focus of this new volume is much broader, and covers not only the essential procedures for the production of linear peptides but also more advanced techniques for preparing cyclic, side-chain modified, phospho- and glycopeptides. Many other methods also deserving attention have been included: convergent peptide synthesis; peptide-protein conjugation; chemoselective ligation; and chemoselective purification. The difficult preparation of cysteine and methionine-containing peptides is also covered, as well as methods for overcoming aggregation during peptide chain assembly and a survey of available automated instrumentation.

Influence of Inert Gas Bubbling on Diffusion at the Cathode During Reduction of Metals in Aqueous Solutions

1995 ◽  
Vol 15 (1-4) ◽  
pp. 137-138
Author(s):  
A. I. BEGUNOV ◽  
V. N. KULKOV ◽  
V. G. GIMELSTEIN
Keyword(s):  
Aqueous Solutions ◽  
Inert Gas ◽  
Gas Bubbling

Researching Your Topic

2021 ◽  
pp. 80-89
Author(s):  
Brenda Hargroves
Keyword(s):  
Research Methods ◽  
Subject Matter ◽  
History Plays ◽  
Correct Method ◽  
Different Types ◽  
The Subject

This chapter discusses what a researcher should consider before examining a topic or project. Understanding the context of the topic, the audience, and why the subject matter is important are critical first steps. Identifying issues surrounding the topic and determining whether history plays a role in the process must also be considered. Different types of research methods and choosing the correct method to facilitate meeting the research objective are addressed. Lastly, the author suggests various tools that should be selected to examine a topic or project.

Instrumentation for automated solid phase peptide synthesis

1999 ◽  
Author(s):  
Linda E. Cammish ◽  
Steven A. Kates
Keyword(s):  
Amino Acid ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Reaction Vessel ◽  
Automated System ◽  
Polymeric Support ◽  
Simple Filtration ◽  
Subsequent Activation ◽  
Selection Of

The concept of solid phase peptide synthesis introduced by Merrifield in 1963 involves elongating a peptide chain on a polymeric support via a two-step repetitive process: removal of the Nα-protecting group and coupling of the next incoming amino acid. A second feature of the solid phase technique is that reagents are added in large excesses which can be removed by simple filtration and washing. Since these operations occur in a single reaction vessel, the entire process is amenable to automation. Essential requirements for a fully automatic synthesizer include a set of solvent and reagent reservoirs, as well as a suitable reaction vessel to contain the solid support and enable mixing with solvents and reagents. Additionally, a system is required for selection of specific solvents and reagents with accurate measurement for delivery to and removal from the reaction vessel, and a programmer to facilitate these automatic operations is necessary. The current commercially available instruments offer a variety of features in terms of their scale (15 mg to 5 kg of resin), chemical compatibility with 9-fluorenylmethyloxycarbonyl/tert-butyl (Fmoc/tBu) and tert-butyloxycarbonyl/ benzyl (Boc/Bzl)-based methods, software (reaction monitoring and feedback control), and flexibility (additional washing and multiple activation strategies). In addition, certain instruments are better suited for the synthesis of more complex peptides such as cyclic, phosphorylated, and glycosylated sequences while others possess the ability to assemble a large number of peptide sequences. The selection of an instrument is dependent on the requirements and demands of an individual laboratory. This chapter will describe the features of the currently available systems. As the field of solid phase synthesis evolved, manufacturers designed systems based on the synergy between chemistry and engineering. A key component to an instrument is the handling of amino acids and their subsequent activation to couple to a polymeric support. The goal of an automated system is to duplicate conditions that provide stability to reactive species that might decompose. Standard protocols for automated synthesis incorporate carbodiimide, phosphonium, and aminium/uronium reagents, preformed active esters, and acid fluorides. For further details on coupling methods, see Chapter 3. A second issue related to coupling chemistry is the time required to dissolve an amino acid and store this solution.

scholarly journals Management and Usage of Nitrogen Systems on Liquefied Natural Gas (LNG) Carriers

2018 ◽  
Vol 55 (1) ◽  
pp. 219-227
Author(s):  
Renato Ivče ◽  
Igor Rudan ◽  
Mateo Rudan
Keyword(s):  
Natural Gas ◽  
Liquefied Natural Gas ◽  
Nitrogen Management ◽  
Inert Gas ◽  
General Knowledge ◽  
Specific Knowledge ◽  
Cargo Handling ◽  
Professional Interest ◽  
The Subject ◽  
Liquefied Gas

The importance of liquefied natural gas (LNG) vessels and the technology that enables their operations is steadily growing. Hence, in addition to professional interest, the general public also displays a considerably large interest in this issue. Today LNG carriers belong to the category of the most technologically developed vessels and therefore managing these vessels requires not only the general knowledge but also the specific knowledge relating to their cargo handling systems. To ensure the safe and economical transport of LNG by sea and to minimize the risk of fire or explosion it is necessary to understand the properties of LNG and nitrogen, an inert gas used in all phases of the carriage and transfer of liquefied gas. The subject of this research is the overall process of nitrogen management in daily operations on board LNG carriers. The aim of the research is to explain, evaluate and define the various applications of nitrogen systems on LNG carriers.

New Reaction Vessel for Solid-Phase Peptide Synthesis

1972 ◽  
Vol 50 (7) ◽  
pp. 755-757 ◽  
Author(s):  
W. K. Park ◽  
D. Regoli
Keyword(s):  
Peptide Synthesis ◽  
Negative Pressure ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Reaction Vessel ◽  
Phase Method ◽  
Gas Dispersion ◽  
Solid Phase Method ◽  
The One

The vessel for the synthesis of peptides by the solid-phase method consists of a round flask with one side-arm and three stopcocks. The side-arm is used to attach the vessel to a wrist-shaker and to insert a gas dispersion tube for the cleavage of the synthesized peptide. Solvents and reagents are introduced from the stopcock on the top and removed from the one at the bottom, by applying negative pressure and by opening the lateral stopcock at the same time.

scholarly journals The diamagnetic susceptibilities of salts forming ions with inert gas configurations - Part I—The halides of sodium and potassium

1934 ◽  
Vol 147 (860) ◽  
pp. 88-100 ◽  
Keyword(s):  
Diamagnetic Susceptibility ◽  
Theoretical Work ◽  
Systematic Investigation ◽  
Inert Gas ◽  
Experimental Conditions ◽  
The Past ◽  
The Subject ◽  
Complete Investigation ◽  
Sodium And Potassium ◽  
Quantitative Nature

Although the subject of diamagnetic susceptibility has attracted the attention of many experimental and theoretical investigators during the past decade, it is remarkable that no complete systematic investigation of the susceptibilities of salts forming ions with inert gas configurations has been made. As a result, in comparing experimental and theoretical work, results for various salts obtained by quite different methods are used in conjunction with one another, and it is hardly surprising that the agreement should be of an approximate quantitative nature only in view of the wide discordance of the experimental results. The work of Ikenmeyer is the most complete investigation, but here the susceptibilities of certain salts, notably the fluorides, have not been measured. This is a serious omission for the data upon fluorides should prove to be amongst the most interesting. The present investigation is part of an attempt to obtain a series of results under the same experimental conditions and with the same apparatus, in order that the comparative values so obtained may be as accurate as possible.

scholarly journals Hydrogen removal form molten aluminum by inert gas bubbling.

1990 ◽  
Vol 40 (4) ◽  
pp. 290-297
Author(s):  
Ryotatsu OTSUKA ◽  
Shigemi TANIMOTO ◽  
Kazuo TOYODA ◽  
Masashi SAKAGUCHI
Keyword(s):  
Molten Aluminum ◽  
Inert Gas ◽  
Gas Bubbling

Use of phenylacetyl group for protection of the lysine Nε-amino group in synthesis of peptides

1981 ◽  
Vol 46 (8) ◽  
pp. 1983-1989 ◽  
Author(s):  
František Brtník ◽  
Tomislav Barth ◽  
Karel Jošt
Keyword(s):  
Peptide Synthesis ◽  
Peptide Chain ◽  
Amino Group ◽  
Protecting Group ◽  
Lysine Vasopressin

Nε-Phenylacetyllysine was used in the synthesis of deamino-lysine-vasopressin. The phenylacetyl protecting group is stable under conditions of peptide synthesis and can be removed by action of penicillin amidohydrolase (E.C.3.5.1.11) without damaging the built peptide chain.

The thermal decomposition of aromatic compounds - I. Chlorobenzene

1954 ◽  
Vol 224 (1158) ◽  
pp. 308-321 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Aromatic Compounds ◽  
Reaction Vessel ◽  
Inert Gas ◽  
Unimolecular Reaction ◽  
Chain Reaction ◽  
Homogeneous Process ◽  
Carbon Compounds ◽  
Chain Character ◽  
Limiting Value

The thermal decomposition of chlorobenzene has been studied in the temperature region 720 to 800° C. The decomposition is a predominantly homogeneous process and leads to the production of approximately one molecule of hydrogen and one molecule of hydrogen chloride for every molecule of chlorobenzene decomposed. No gaseous carbon compounds are formed, and all the combined carbon and the remaining hydrogen are deposited on the walls of the reaction vessel as a hard, shiny, graphite-like solid. The structure of this deposit was examined by electron diffraction and compared with those produced by pyrolysis of other organic compounds. The thermal decomposition of chlorobenzene is kinetically composite. The partial chain character of the reaction is indicated by the lowering of the decomposition rate to the same limiting value on addition of both nitric oxide and ammonia. It is confirmed by the acceleration produced by an inert gas and by the retardation caused by an increase in the surface. The mechanism of the chain reaction is considered, and a possible chain cycle is proposed. The nature of the fully inhibited reaction is also discussed, and though the evidence is to some extent conflicting it is concluded that it is probably a unimolecular reaction.

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