Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The goal of this study was to clarify the effects of dextran 10 kDa on the properties of spray-freeze-dried microparticles for use with ballistic injectors. A novel carrier of trehalose, mannitol, and the polymer is known to maximize particle density. Measurements of T'(g) showed that the dextran anti-plasticizes the trehalose/mannitol, but also undergoes phase separation. The product temperature exceeded T'(g) during primary drying. The collapsed particles can therefore be explained by plastic flow of the freeze concentrate. DSC of the powder showed T(g) at 45 degrees C and, in the first scan, a wide endothermic melting peak caused by mannitol recrystallization. Catalase showed 35% activity loss on rehydration of its spray freeze-drying (SFD) powder, which was improved in the TM/D (3:3:4) formulation, but not up to that level seen with either trehalose or mannitol alone. The dextran 10 kDa, which is vital to maximize particle density, was therefore detrimental to protein integrity during SFD, as also found with a 65-72 kDa dextran. Hydroxyethyl starch (HES) 200 kDa gave similar, limited stabilizing effects on the protein. The proportion of polymer in the formulation should be low to minimize protein damage, whilst high enough to give required particle morphology and density.
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PMID:Dextran or hydroxyethyl starch in spray-freeze-dried trehalose/mannitol microparticles intended as ballistic particulate carriers for proteins. 1727 46

Partitioning of six typical globular proteins with molecular weights ranging from 12.6 to 250 kDa was investigated using an aqueous two-phase system formed by heating a solution containing the individual proteins and n-dodecyldimethylphosphine oxide (APO12) above the cloud point of the nonionic surfactant (approximately 40 degrees C). The partition coefficient, Kp, was much greater at 55 than 45 degrees C and depended on both APO12 and protein concentrations. The value of Kp for bovine beta-lactoglobulin (beta-L) varied from 2 to 60, and was larger for 1.0mg/mL solutions than for ovalbumin (2x greater), bovine serum albumin (3x greater) and lysozyme (12x greater). Catalase and cytochrome c were apparently denatured in the presence of 20mg/mL of APO12 and were not investigated. Large values of Kp for beta-L resulted when the pH of APO12 mixtures containing phospholipids and either a cationic or anionic surfactant in molar ratios of 10:0.5:1.0 was partitioned above or below the isoelectric point of the protein, respectively. The affinity of the proteins for the APO12 micelle was responsible for partitioning of the proteins into the upper phase. Finally, DSC studies with beta-L showed that the denaturing action of n-decyldimethylphosphine oxide (APO10) below 61 degrees C and APO12 at 22 degrees C was reversed by dilution or dialysis, respectively.
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PMID:A new micellar aqueous two-phase partitioning system (ATPS) for the separation of proteins. 1788 41