Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.2.3.23 (GAS)
 957 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gaseous CO2 was used as an antisolvent to induce the fractional precipitation of alkaline phosphatase, insulin, lysozyme, ribonuclease, trypsin, and their mixtures from dimethylsulfoxide (DMSO). Compressed CO2 was added continuously and isothermally to stationary DMSO solutions (gaseous antisolvent, GAS). Dissolution of CO2 was accompanied by a pronounced, pressure-dependent volumetric expansion of DMSO and a consequent reduction in solvent strength of DMSO towards dissolved proteins. View cell experiments were conducted to determine the pressures at which various proteins precipitate from DMSO. The solubility of each protein in CO2-expanded DMSO was different, illustrating the potential to separate and purify proteins using gaseous antisolvents. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE) was used to quantify the separation of lysozyme from ribonuclease, alkaline phosphatase from insulin, and trypsin from catalase. Lysozyme biological activity assays were also performed to determine the composition of precipitates from DMSO initially containing lysozyme and ribonuclease. SDS-PAGE characterizations suggest that the composition and purity of solid-phase precipitated from a solution containing multiple proteins may be accurately controlled through the antisolvent's pressure. Insulin, lysozyme, ribonuclease, and trypsin precipitates recovered substantial amounts of biological activity upon redissolution in aqueous media. Alkaline phosphatase, however, was irreversibly denaturated. Vapor-phase antisolvents, which are easily separated and recovered from proteins and liquid solvents upon depressurization, appear to be a reliable and effective means of selectively precipitating proteins.
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PMID:Protein purification with vapor-phase carbon dioxide. 1009 36

The protein lysozyme has been precipitated as amorphous nanoparticles from a DMSO solution using dense carbon dioxide as antisolvent, by applying the so-called gas antisolvent recrystallization technique in a 400-mL precipitator. The objective is to investigate the possibility of tuning the particle properties by changing the key process parameters, namely, antisolvent addition rate, initial solute concentration, and temperature. It is shown that none of these operating parameters has a major effect on the average particle size or the particle size distribution. The former is mostly between 200 and 300 nm and exhibits no evident trend. The latter is always unimodal and rather narrow and exhibits increasing agglomeration at higher temperature and initial solute concentration. Up to 75% of the protein activity measured in the starting crystalline material is retained by the precipitated amorphous nanoparticles. The present experimental results compare well with data about the same system obtained in a different experimental setup, which were previously reported in the literature, thus pointing at the reproducibility and robustness of GAS antisolvent recrystallization. Moreover, these are consistent with the theoretical understanding of gas antisolvent recrystallization as achieved by using a recently developed model of the process.
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PMID:Precipitation of lysozyme nanoparticles from dimethyl sulfoxide using carbon dioxide as antisolvent. 1267