The Semi-Preparative Separation of Peptides on Reversed Phase Silica Packed into Radially Compressed Flexible-Walled Columns

On hen egg fractionation: applications of liquid chromatography to the isolation and the purification of hen egg white and egg yolk proteins

Liquid chromatography has been used as a means of egg protein analysis or as a method for the purification of egg proteins. Several chromatographic methods, including gel permeation, ion-exchange, reversed-phase, hydrophobic interaction, and immobilized-ligand-affinity chromatography, have been carried out for the separation or the purification of egg yolk or egg white proteins. Ion-exchange chromatography appears to be the most frequently used method for protein isolation and it is the easiest to adapt to a process scale. From an analytical point of view reversed-phase chromatography is, at the moment, the recommended method for egg white analysis. Egg white has been fractionated more often by liquid chromatography than has egg yolk. Several chromatographic methods have been developed on a laboratory scale, but the application of these techniques on an industrial scale remains limited.

Applications of preparative high-performance liquid chromatography to the separation and purification of peptides and proteins

The basic differences between the problems encountered in the development of the analytical and preparative applications of high-performance liquid chromatography are analyzed and the principles of optimization of a preparative separation outlined. The application of these principles to the purification of peptides and proteins are discussed with emphasis on the specific problems raised by the separation of high-molecular-mass compounds. The relative advantages and inconveniences of displacement and overloaded elution are presented. The applications of the various retention modes of liquid chromatography (ion exchange, reversed-phase adsorption, hydrophobic interactions, size exclusion and bioaffinity) to the separation of various peptide and protein mixtures and/or to the extraction and purification of some of these compounds are reviewed. Separation performance reported in the literature are summarized in table form.

High-performance liquid chromatography of amino acids, peptides and proteins. LXIII. Reversed-phase high-performance liquid chromatographic characterisation of several polypeptide and protein hormones

The chromatographic behaviour on alkylsilicas of a variety of hormonal proteins is described. Optimization of resolution and recovery of these protein hormones, which included porcine relaxins, human chorionic gonadotropin, human placental lactogen, pituitary derived growth hormone and adenohypophyseal glycoprotein hormones, was achieved by manipulation of both mobile and stationary phase parameters. With standard stainless-steel analytical columns (10-30 cm X 0.4 cm) packed with meso- or macro-porous n-alkylsilica supports these proteins can be readily fractionated at the semi-preparative level with separation times generally under 90 min using elution systems directly compatible with subsequent methods of primary structure determination or biological functional analysis. The effects of changes in several experimental parameters on peak symmetry, retention and recovery are described.

Application of analytical and semi-preparative high-performance liquid chromatography to anthracyclines and bis-anthracycline derivatives

Efficient high-performance liquid chromatographic (HPLC) methods have been developed for routine analysis of a number of anthracycline derivatives using reversed-phase muBondapak C18 columns and an isocratic methanol-water-ammonium carbonate (or acetate) solvent system. The rates of formation of bis-daunomycin derivatives of alpha, omega-dicarboxylic acid hydrazides have been investigated using the analytical methods developed. It has been demonstrated that the reaction proceeds via an intermediate mono-hydrazone. Both the mono- and bis-hydrazones have been isolated by preparative HPLC.

High-performance liquid chromatography of neuropeptides using radially compressed polythene cartridges

This study was designed to assess practically the suitability of different C18 reversed-phase radially compressed polythene cartridges (Radial-Pak, Waters Assoc.) in two types of radial-compression systems, for the separation and analysis of various neuropeptides at both high (less than 5 micrograms) and low (greater than 100 pg) levels in biological extracts and to compare them with well established techniques using stainless-steel columns. A solvent system fully compatible with both radially compressed and steel columns is described. The completely volatile mobile phase (acetonitrile gradient containing trifluoroacetic acid) allows ultraviolet detection below 215 nm, gives good resolution and is readily compatible with the further radioimmunoassay and bioassay of collected fractions. The efficiency of radially compressed 5 and 10 microns "capped" and "non-capped" C18 silica supports and slurry-packed steel columns has been assessed by: (1) separation and recovery of a complex standard mixture of neuropeptides; (2) separation and subsequent identification of degradation products formed during the incubation of neurotensin with rat cortical synaptosomes; (3) analysis of alpha-melanotropin and corticotropin-(18-39) in tissue culture media containing varying amounts of foetal calf serum; and (4) characterization of corticotropin-like immunoreactivity in human cerebrospinal fluid. The Z-module fitted with the capped 10-microns irregular C18 silica cartridge gave better resolution than with the mu Bondapak steel column but the selective retention was similar. The back-pressures in the Z-module are much reduced (approximately 13 bar at 1 ml/min); therefore, flow-rates may be increased and analysis times greatly reduced. In order to obtain good resolution with the RCM-100 module which uses a non-capped stationary phase, a salt must be added (e.g. 15 mM sodium chloride) to the mobile phase to reduce polar interactions between the peptide and the free silanol groups on the stationary phase. This makes the solvent non-volatile and therefore less useful.

High-performance liquid chromatography of amino acids, peptides and proteins. XLVIII. Retention behaviour of tryptic peptides of human growth hormone isolated by reversed-phase high-performance liquid chromatography: a comparative study using different chromatographic conditions and predicted elution behaviour based on retention coefficients

The retention behaviour of the tryptic peptides of human growth hormone under a variety of reversed-phase chromatographic conditions has been investigated. By using water-acetonitrile gradients containing phosphate, bicarbonate, trifluoroacetate, or heptanesulphonate buffers, the influence of these ionic modifiers on peptide selectivity with several different alkylsilicas has been examined. Comparisons of observed and predicted retention behaviours for the various tryptic peptides in the different chromatographic systems are described. Application of these systems to the isolation of deamidated forms of human growth hormone is presented.

Isolation of the Maclura pomifera hemagglutinin on a deoxymelibiotol affinity support and preliminary characterization by buffer electrofocusing and high-performance liquid chromatography

Maclurin, the potent non-specific blood-group hemagglutinin present in extracts of Maclura pomifera, has been purified by a new biospecific affinity-chromatographic procedure. Additional studies have indicated that this hemagglutinin occurs as five closely related tetrameric protein isoforms derived from two non-covalently-linked polypeptide chains, mol. wts. ca. 10,000 and 13,000 respectively. Buffer electrofocusing fractionated the lectin into 12 components; the major isolectin exhibited an isoelectric point at pH 4.8.