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Validation of Recovery and Purification Processes
Published in James Agalloco, Phil DeSantis, Anthony Grilli, Anthony Pavell, Handbook of Validation in Pharmaceutical Processes, 2021
Precipitation can be caused by desalting, salt, nonionic polymers, or miscible organic solvent addition, by adjusting the pH to the isoelectric point of a given protein to minimize its solubility, or by increasing temperature.23,24 Salts can precipitate proteins by “salting out” effects. The effectiveness of various salts is determined by the Hofmeister series, with anions being effective in the order citrate > PO4 = > SO4 = > CH3COO− > Cl− > NO3−, and cations in the sequence NH4+ > K + > Na+.25 Ammonium sulfate is the most commonly used precipitant. The organic solvents commonly used for protein precipitation are acetone and ethanol; these are typically added with in-line mixers to minimize regions of high solvent concentration causing protein denaturation or local precipitation. Nonionic water-soluble polymers, such as polyethylene glycol, are also effective precipitants.
Role of Extracellular Polymeric Substances (EPS) in Cell Surface Hydrophobicity
Published in Y.V. Nancharaiah, Vayalam P. Venugopalan, Microbial Biofilms in Bioremediation and Wastewater Treatment, 2019
Feishu Cao, Gilles Guibaud, Isabelle Bourven, Yoan Pechaud, Piet N.L. Lens, Eric D. van Hullebusch
Usually, a decreasing salt gradient is applied to elute samples from the column so that the hydrophobic interactions can be intensified. The salts frequently used are called anti-chaotropic salts (also kosmotropic or lyotropic salt), which includes sodium, potassium, ammonium sulfate, sodium nitrate, and sodium chloride in phosphate buffer at pH 7 (Baca et al. 2016). These salts have a higher polarity to bind water tightly, and their presence in the mobile phase benefits the stabilization of protein structure (Xia et al. 2004). By using these salts, the exclusion of water between the proteins and the ligand surface can be induced, and thus, promotes the hydrophobic interactions and protein precipitation (salting-out effect) (Kunz et al. 2004). However, studies have shown that the retention of hydrophobic molecules in HIC is affected by the interplay of different factors (Table 2), such as pH, salt type and concentration, ligand type and density in the column material, protein folding upon adsorption and kinetic of protein spreading (Nfor et al. 2011, Mahn et al. 2007, Haimer et al. 2007, Jungbauer et al. 2005, Xia et al. 2004, Perkins et al. 1997).
Enzyme Catalysis
Published in Harvey W. Blanch, Douglas S. Clark, Biochemical Engineering, 1997
Harvey W. Blanch, Douglas S. Clark
Protein precipitation is usually an intermediate step toward final purification, since precipitates are typically impure. They may be aggregates of several proteins and/or contain large amounts of adsorbed salts. Impurities may be particularly troublesome when the original mixture contains many proteins that have similar properties with respect to precipitation. In such a case, precise fractionation of one protein from another may be possible, albeit difficult. Indeed, recovering a target protein from a mixture is one of the most demanding challenges in designing a precipitation scheme.
Factors affecting therapeutic protein purity and yield during chromatographic purification
Published in Preparative Biochemistry & Biotechnology, 2023
Che Haznie Ayu Che Hussian, Wai Yie Leong
The purification of proteins is not a simple process. Protein precipitation, aggregation, solubility, surface modifications, and surface hydrophobicity are some of the numerous parameters that can influence the purification of proteins. However, the chromatography process also has the potential to influence the purifying process. As a result, the primary focus of this review was placed on the elements that have a significant potential to influence both the purity and the yield during the chromatographic purification process. It is necessary to optimize each of these aspects (parameters) in accordance with the manufacturing standard that has been established in order to achieve a high yield and purity of enzymes.
Progress in pretreatment of methadone: an update since 2015
Published in Preparative Biochemistry & Biotechnology, 2023
Several traditional pretreatment methods have been developed and applied for the determination of methadone for many years. They played a fundamental role in the pretreatment of methadone with simple procedures and short extraction time. Most of them are suitable for instant detection and have always been applied with electrochemical sensors to detect methadone. These traditional methods include protein precipitation, dilution, solid-liquid extraction method, centrifugation, and enzyme digestion method which are cheap and can be done with simple equipment without complicated procedures.