High-performance liquid chromatography of amino acids, peptides and proteins. XLVII. Analytical and semi-preparative separation of several pituitary proteins by high-performance ion-exchange chromatography

Characterization and application of strong ion-exchange membrane adsorbers as stationary phases in high-performance liquid chromatography of proteins

Filtration membranes carrying strong cation- or anion-exchange groups on their surface were evaluated for their potential as membrane adsorber stationary phases in the high-performance liquid chromatography of proteins. The membranes are commercially available and can be obtained inserted into ready-to-use filter holders. Owing to their thinness (170-190 microns), the pressure drop of the membranes is extremely low. Flow-rates of up to 65 ml min-1 per unit became thus possible. The low pressure drop of a single membrane layer also permitted an effortless scaling up, as a stack of several membranes or filter units could be used, if necessary. Sample distribution, protein binding capacity, elution conditions, separation efficiency and recovery were investigated as a function of the flow-rate. The time required for the separation of certain protein mixtures could be reduced to less than 1 min. Appropriate conditions were defined for the separation of human serum and for the isolation of subtilisin Carlsberg and beta-galactosidase from cell culture supernatants.

Purification of canine prolactin and growth hormone by fast protein liquid chromatography

Prolactin and growth hormone are two peptide hormone with a very similar structure. A simple method is described for the simultaneous purification of these two peptides from canine pituitary extract by fast protein liquid chromatography. After extraction at pH 5.0 and 9.6 and anion-exchange chromatography on a MonoQ column, prolactin and growth hormone are then separated by gel filtration chromatography on two Superose columns coupled in series. The different fractions of the purification scheme are checked for the presence of the peptide hormones by sodium dodecyl sulphate gel electrophoresis in the Pharmacia PhastSystem. Each hormone is also characterized by its behaviour in a Western Blotting Detection System.

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.

Influence of bovine LH tracer quality on levels of LH in GnRH-treated cows

Chromatography of 125I-bovine LH (LER-1716-2 and USDA-I-1) by means of anion exchange high performance liquid chromatography (HPLC) revealed two main peaks of radioactivity regardless as to whether or not the tracer was initially purified on cellulose CF11. The content of radioactivity in the first peak tended to increase as the storage time of the bLH preparation, either before or after iodination, increased. The first peak of radioactivity after HPLC fractionation either with or without cellulose adsorption consisted of material with low binding ability to bLH antiserum (6.9% +/- 0.5 and 13.0% +/- 1.0, respectively) and high binding ability to ovine LH alpha antiserum (51.0% +/- 2.7 and 35.2% +/- 3.6, respectively). The average ratio of alpha-subunit immuno-reactivity to 125I-bLH immunoreactivity in this material was 7.4 +/- 0.1 and 2.7 +/- 0.2, respectively (P less than 0.001). Peaks in 125I-bLH radioactivity and 125I-bLH immunoreactivity had different elution times. Radioimmunoassays with tracers obtained from fractions derived from the first radioactive peak after HPLC chromatography (i.e. 125I-bLH-LER-1716-2) both with and without cellulose adsorption, yielded significantly lower mean plasma LH levels in GnRH-treated cows compared with the control tracer routinely purified only on cellulose CF11 (e.g. 5.7 vs. 8.2 micrograms/; 4.6 vs. 8.2 micrograms/l). Plasma LH levels in GnRH-treated cows were significantly (P less than 0.001) lower as measured by radioimmunoassay utilizing 125I-USDA-blH-I-1 tracers than by radioimmunoassays utilizing 125I-blH-LER-1716-2 tracers (i.e. either Y = 0.17 + 0.75X or Y = 1.18 + 0.60X).

Rapid protein profiling with a novel anion-exchange material

A new anion-exchange material has been developed which allows very rapid resolution of protein mixtures. The Microanalyzer MA7P matrix consists of small (7 micron), spherical, non-porous, polymethacrylate beads with polyethyleneimine (PEI) covalently coupled to the surface. When packed 30 X 4.6 mm I.D. columns, this matrix is particularly well suited for applications in which 1-300 micrograms of a protein mixture must be resolved in a minimum of time. Recoveries of injected proteins are usually quantitative, even when the amounts of individual proteins are in the submicrogram range. Chromatography on Microanalyzer MA7P columns is characterized by very narrow bandwidths, even at relatively high flow-rates. This is due to the combined effects of short column length, high selectivity, and the lack of velocity-dependent bandbroadening attributable to diffusion into and out of pores. These columns have no discernable gel filtration effects in the molecular weight range from 10(3) to 10(6) daltons. Columns are very rapidly equilibrated with new solvents, further reducing cycle-to-cycle times.

High-performance liquid chromatography of amino acids, peptides and proteins. LVII. Analysis of radioiodinated thyrotropin polypeptides by reversed-phase high-performance liquid chromatography

The chromatographic behaviour of bovine and human thyrotropin, radiolabelled stoichiometrically with lactoperoxidase, on octadecylsilicas and other reversed-phase n-alkylsilicas has been investigated. As part of this investigation the effects of a variety of elution systems on resolution and recovery have been examined. Analysis of the tryptic peptides of radioiodinated bovine thyrotropin (bTSH) preparations by reversed-phase high-performance liquid chromatographic mapping methods resulted in the separation of more than fourteen major radioactive peptide components. The data indicate that bTSH is radioiodinated with unequal incorporation into both the alpha- and beta-subunits. Further, assessment of the level of microheterogeneity of radiolabelled bTSH preparations can be achieved with these reversed-phase techniques.

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.