Search

INTRODUCTION Cell culture techniques are routinely used to produce proteins intended for use as biopharmaceuticals. The culture conditions must be optimized to ensure that the protein is produced without structural [...]

INTRODUCTION Glycosylation is a post-translational, modification of proteins that occurs in all eukaryotic cells. The sugar chains on glycoproteins can mediate biological, activity, play a role in receptor-mediated recognition, increase [...]

Peptide mapping continues to be the preferred technique for the comprehensive characterization of biopharmaceutical products. Its applications include: the identification of proteins based on the elution pattern of peptide fragments, [...]

Scale-up from UPLC technology to preparative LC is readily achieved using preparative OBD columns and typical scaling equations and principles. UltraPerformance LC (UPLC) has been widely accepted by chromatographers because [...]

A new total application solution for the analysis of amino acids has recently been developed. The analysis provides better resolution and sensitivity than has been possible in existing methods. The [...]

Additional UPLC chemistries provide flexibility for methods development. Ultra Performance LC[TM] (UPLC[TM]) enables chromatographers to meet the challenges of developing separations that completely characterize the constituents of samples by providing [...]

Hydrophilic interaction chromatography (HILIC) can improve HPLC assays for polar compounds that retain poorly using reversed-phase HPLC. Combining this chromatographic technique with highly efficient 1.7 µm UPLC BEH particles results [...]

The article offers information on the instrument considerations in the transfer of chromatographic methods and discusses the challenges associated with the activity. Topics include the techniques for bringing the individual modules of the two systems into alignment so that equivalent results are obtained; autosampler in chromatographic system will introduce a specified volume of sample into the fluid stream leading to the column; and a detector that can affect the method transfer.

Successful transfer of chromatographic methods often proves more challenging than expected. This three-part article series will summarize the details of this process with particular attention to the sources of confusion and to some suggested solutions for the observed difficulties. In part I, the focus will be on the method as a whole and considerations for avoiding and eliminating ambiguities and inconsistencies between laboratories. In part II, the characterization of the system will be emphasized. In part III, emphasis will be placed the techniques for bringing the modules of the two systems into alignment. [ABSTRACT FROM AUTHOR]

Immunization of female rabbits and mice with the sperm-specific isozyme of lactate dehydrogenase, LDH-C4, significantly reduced their fertility. Similar studies have been extended to nonhuman primates. Two female baboons, immunized with human LDH-C4, produced low antibody titers. These titers were markedly enhanced by booster injections of murine LDH-C4. An additional seven female baboons responded with relatively high antibody titers after receiving murine LDH-C4as both priming and booster dosages. All nine females received injections of murine LDH-C4at varying times determined by serum titer levels during fertility studies. These antisera reacted with human, mouse, and baboon LDH-C4.

Peptide fragments of lactate dehydrogenase-C4(LDH-C4) that contain antigenic sequences of the native protein have been identified. The present study describes the binding to murine and human spermatozoa of antibodies that were produced against synthetic peptides containing two of these sequences.Rabbits were immunized with peptides designated MC5–15and MC211–220, conjugated to diphtheria toxoid (DT). Antisera from these rabbits were tested for binding to washed mouse epididymal sperm or human ejaculated spermatozoa using a solid-phase radioimmunoassay. Antisera bind to mouse sperm in this system at dilutions of 1:64,000. When these antisera are first absorbed with the native LDH-C4molecule, significant inhibition of binding to sperm results. Antisera to both DT-MC5–15and DT-MC211–220bind to human sperm with similar but weaker patterns than seen with mouse sperm. These data indicate that the immune response to synthetic peptides containing antigenic sequences of LDH-C4includes antibodies that specifically bind to this enzyme on the surface of sperm. In addition, there are shared antigenic sequences between mouse and human LDH-C4, including the MC5–15and MC211–220peptides.

The article presents the result of glycan separation using the ACQUITY ultra performance liquid chromatography (UPLC) instrument and fluorescence (FLR) detector. The chromatograms of N-linked oligosaccharides released from human immunoglobulin G (IgG), which are composed of mannose, complex, hybrid and sialylated glycans, are graphically represented. The graphical representation of glycans from bovine fetuin is also provided.