Dilatometrische Untersuchung der Hitzedenaturierung von Eiweißlösungen

Haurowitz, Felix

doi:10.1007/bf01496829

Cited by 15 publications

(1 citation statement)

References 8 publications

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“…First attempts to measure changes of the volume by dilatometry failed [17,18]; similarly no noticeable differences in the hydration of native and denatured proteins could be detected 11191. However, indirect evidence was gained from denaturation experiments a t Lugh hydrostatic pressure [20,21] which proved the precipitation of proteins to be retarded a t pressures up to 700 atmospheres, while a t higher hydrostatic pressure complete coagulation was observed [22,23].…”

Section: Discussionmentioning

confidence: 99%

Volume Changes in the Isoelectric Heat Aggregation of Serum Albumin

Jaenicke

1971

Eur J Biochem

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High precision dilatometry and buoyancy measurements in a quartz spring balance show that the change of partial specific volume of serum albumin accompanying aggregation a t the isoelectric point is positive, and of the order of A V = + i . 2 -+ 0.1 pl/g protein. Experiments a t high hydrostatic pressure ( < 3000 atmospheres) confirm this result, the aggregation reaction being suppressed significantly.As it appears by measurements of optical rotatory dispersion that the molecular secondary structure is kept essentially unchanged during the reaction, it is suggested that the water of hydration of the monomers, which probably is in a state of high density due to electrostriction, is partially eliminated from the molecular surface in the state of aggregation.The action of heat on globular proteins leads to conformational changes (denaturation) and/or changes of particle size (aggregation). As shown by kinetic experiments, the correlation between t,he two processes depends on the inter-and intramolecular electrostatic potential of the charges on the polyampholytic molecules [1,2], maximum rate of aggregation being observed in the isoelectric point, while maximum denaturation occurs a t high positive or negative net charge of the molecules. As a consequence one might expect the "isoelectric coagulation" [3,4] to represent a polymerization reaction based on unaltered native molecules. I n fact, spectroscopic results [2] substantiate this concept, suggesting a phase separation rather than conformational changes of the reacting monomers to be involved in the coagulation process.I n order to characterize the state of the isolated (monomeric) molecule as compared to the coagulated system, differences in conformation and in the solvent-solute interactions have to be analyzed. I n this context, volume change data may provide useful criteria for structural alterations in both the solvent and the solute or for changes in the solvent-solute interactions [5].The following results are based on dilatometry and water release experiments in a quartz spring balance. I n addition experiments at high hydrostatic pressure are presented. Parallel conformational analyses are performed using optical rotatory dispersion spectroscopy. MATERIALS AND METHODSBovine serum albumin of highest purity (Sigma, crystallized and lyophilized, and Behring-Werke, Dedicated to Professor F. Lynen on occasion of his sixtieth birthday. trocken, reinst) was used without further purification. Tobacco mosaic virus protein from the common strain of tobacco mosaic virus was prepared according to [6]. Reagents were of A-grade purity; bidistilled water was used throughout. Buffers were deaerated by heating to 90 "C or (in case of protein solutions) by keeping the solutions under reduced pressure for several minutes. Protein concentration (cp) was calculated from the absorbance a t 280 nm and from dry weight determination after exhaustive dialysis against water.The degree of aggregation was estimated from light-scattering [4], centrifugation and ultracentrifugation ...

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Section: Discussionmentioning

confidence: 99%

Volume Changes in the Isoelectric Heat Aggregation of Serum Albumin

Jaenicke

1971

Eur J Biochem

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Über die Umwandlung einiger Sphäroproteine in Linearproteine bei Desaminierung

Jirgensons¹

1943

J. Prakt. Chem.

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Anschließend an die früheren Untersuchungen über das Desaminocasein wurde auch die Viscosität der Lösungen von Desaminoalbumin und Desaminoedestin gemessen. Untersucht wurde die Abhängigkeit der Viscosität von der Konzentration des Desaminoproteins, von der Zeit, sowie von der Konzentration der Lauge und von Salzkonzentration. Die Lösungen des Desaminoalbumins, ebenso wie die früher untersuchten Lösungen des Desaminocaseins haben eine sehr hohe Viscosität. Auch die Lösungen des Desaminoedestins haben größere Viscosität als entsprechende Lösungen des Edestins. Es wurde die Schlußfolgerung gezogen, daß die Moleküle der verwendeten Sphäroproteine bei Desaminierung in Linearkolloide umgewandelt werden. Die freien Aminogruppen der Lysinradikale haben also einen entscheidenden Einfluß auf die Biegung und Zusammenlagerung der Peptidketten.

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