Partitioning in Aqueous Two-Phase Systems: Theory, Methods, Uses, and Applications to Biotechnology is a collection of papers that discusses the applications of aqueous two-phase systems to problems of separation and extraction of macromolecules, organelles, and cells. Papers focus on the theoretical basis and the practical details of the procedures used. Some of the papers describe in one or a few steps how two components can be separated by the investigator manipulating their partitions so that one component is in one phase and the other component is in the other phase or at the interface. Investigators can also avail of developed batch extractions for plant organelles, cell membranes, nucleic acids, and proteins. The book cites as an example the partitioning of right-side-out and inside-out vesicles (obtained from fragments of thylakoid membranes) to the top and bottom phases, respectively, of a Dx-PEG system. Other papers describe the use of the countercurrent distribution when single extraction steps are not sufficient to produce a separation in materials that do not differ greatly in their partitioning behavior. The collection can prove valuable for bio-chemists, cellular biologists, micro-biologists, and developmental biologists.

A mixture of two polymers, or one polymer and a salt, in an aqueous medium separates into two phases: this phenomenon is useful in biotechn- ogy for product separations. Separation of biological molecules and particles in these aqueous two-phase systems (ATPS) was initiated over 40 years ago by P.-Å. Albertsson, and later proved to be of immense utility in biochemical and cell biological research. A boost in the application of ATPS was seen when problems of separations in biotechnology processes were encountered. Its simplicity, biocompatibility, and amenability to easy scaleup operations make the use of ATPS very attractive for large-scale bioseparations. Despite the advantages ATPS enjoys over other separation techniques, the application of two-phase systems has for a long time been confined to selected labora- ries. Recent years have, however, shown a trend in which increasing numbers of researchers employ two-phase partitioning techniques in both basic and applied research.

Covers the fundamental principles of solute partitioning in aqueous two-phase systems, explains their important practical features, and furnishes methods of characterization. The information provided by the partition behaviour of a solute in an aqueous two-phase system is examined.

"Protein Structure Analysis - Preparation and Characterization" is a compilation of practical approaches to the structural analysis of proteins and peptides. Here, about 20 authors describe and comment on techniques for sensitive protein purification and analysis. These methods are used worldwide in biochemical and biotechnical research currently being carried out in pharmaceu tical and biomedical laboratories or protein sequencing facilities. The chapters have been written by scientists with extensive ex perience in these fields, and the practical parts are well documen ted so that the reader should be able to easily reproduce the described techniques. The methods compiled in this book were demonstrated in student courses and in the EMBO Practical Course on "Microsequence Analysis of Proteins" held in Berlin September 10-15, 1995. The topics also derived from a FEBS Workshop, held in Halkidiki, Thessaloniki, Greece, in April, 1995. Most of the authors participated in these courses as lecturers and tutors and made these courses extremely lively and successful. Since polypeptides greatly vary depending on their specific structure and function, strategies for their structural analysis must for the most part be adapted to each individual protein. Therefore, advantages and limitations of the experimen tal approaches are discussed here critically, so that the reader becomes familiar with problems that might be encountered.

Contributors from European and US universities and corporations review recent developments in the integration of downstream processing and bioconversion, describing their experience with many separation technologies, including some still in the experimental stage. The topics include the construction

General methodology and apparatus: phase diagrams, preparation and analysis of two-phase systems, partioning and affinity partitioning of macromolecules: Proteins, nucleic acids, studies on protein interactionsmolecular structure, charge, hydrophobicity, and conformational chan ges, partitioning and affinity partitioning of particulates,organellesseparation and subfractionation, menbrane: separation and subfractionation, membrane domain analysis, aqueous phase separation in biologicalsystems, aqueous two-phase systems in large-scale process biotechnolo gy, proteins; downstream processing, design of proteins for enhanced extraction, other applications of aqueous phases in biotechnology. Enzymology.

This comprehensive and unique text presents a full overview of downstream processing useful for those new to the concept as well as professionals with experience in the area. The history and theoretical principles of Aqueous Two-Phase Systems (ATPS) are covered in depth. Information on ATPS characterization and application is included, and ATPS equilibria and system parameters that have significant effect on partition behavior are studied. Aqueous Two-Phase Systems for Bioprocess Development for the Recovery of Biological Products addresses specific applications of ATPS for the recovery and partial purification of high molecular weight compounds such as proteins, nucleic acids and polysaccharides, particulate bioproducts such as cells and organelles and low molecular weight compounds. Non-conventional strategies involving ATPS such as affinity systems, continuous liquid-liquid fractionation stages and the recovery from plant extracts are presented. Economic analysis of the application of ATPS in comparison to other fractionation techniques, particularly liquid chromatography, is considered, as are opportunity and current trends in the ATPS research area. Each chapter utilizes the contributors' experimental expertise in traditional and non-conventional ATPS strategies, as well as analysis of areas of opportunity and perspectives on the development and future applications of ATPS in both the lab and larger scale operations. The result is a thorough and singular overview of ATPS which has not been matched by any other text on the market.