Die Wärmeaggregation von Proteinen in Lösung

Stauff, J.; Barthel, H.; Jaenicke, Rainer; Krekel, R.; Ühlein, E.

doi:10.1007/bf01520774

Cited by 16 publications

(2 citation statements)

References 17 publications

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“…Thus, the intra-and interchain thiol ~-~ disulfide exchange reaction can be initiated. This reaction promotes the formation of protein oligomers bridged by disulfide bonds (Jensen, 1959;Stauff et al, 1961;Freidman, 1976Freidman, , 1994. As shown by the obtained results, this simple approach was successful and a population of stable oligomers of a-lactalbumin was obtained.…”

Section: Resultsmentioning

confidence: 97%

“…The role of redox transformations involving thiol and disulfide groups of proteins in the processes of baric aggregation and gelation is poorly understood and in many cases left uncontrolled. Using an analogy between the behaviours of proteins at high pressure and high temperatures or in the presence of strong denaturating agents, it is not difficult to understand that the reactions such as the oxidation of thiol groups and the thiol<--)disulfide exchange may participate intensively in the baric oligomerization and gelation of proteins, especially, in mild basic pHs close to the pKa (8.5-8.8) of cysteine (Jensen, 1959;Stauff et al, 1961;Friedman, 1976;Hayakawa and Nakamura, 1986). Recently, Funtenberger et al (1985) reported that high-pressure treatment at 1.5-4.5kbar in some pH7.0 buffers induces oligomerization of /3-1actoglobulin isolate involving the formation of intermolecular disulfide bonds.…”

Section: Introductionmentioning

confidence: 99%

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Thiol-induced oligomerization of α-lactalbumin at high pressure

Jegouic¹,

Grinberg

Guingant

et al. 1996

J Protein Chem

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Denaturation and aggregation of alpha-lactalbumin at high pressure (up to 10 kbar, 1000 MPa) were studied by means of circular dichroism, gel-permeation chromatography, sodium dodecyl sulfate and gel electrophoresis. It was found that the unfolding of alpha-lactalbumin at high pressure is reversible even in basic pH and at a protein concentration as large as 10%. In these conditions only a negligible fraction of the protein is denatured irreversibly and aggregates. The rate of aggregation of alpha-lactalbumin at high pressure increases significantly in the presence of low-molecular reducing agents such as cysteine, 2-mercaptoethanol, and dithiothreitol. Maximal yield of alpha-lactalbumin oligomerization (over 90%) was achieved in the presence of cysteine at the molar cysteine/protein ratio q = 2 and at pH8.5. Apparent molecular weight of the obtained oligomers was over 500 kDa. It was shown that the size distribution of oligomers can be modulated by varying pH and reducing agent. The size distribution shifts in the direction of very large, poorly soluble particles when pH decreases. Maximal content of the insoluble fraction (about 30%) can be reached at pH 5.5 when cysteine (q = 2) is used as reducing agent. The oligomers of alpha-lactalbumin are stabilized mainly by nonnative interchain disulfide bridges. Circular dichroism measurements point to an additional mechanism of cohesion of polypeptide chains in the oligomers, which is formation of intermolecular beta-sheets.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%