Nomenklatur und einige Eigenschaften der Molkenproteine. 1. Mitt. β‐Lactoglobulin

Sienkiewicz, T.

doi:10.1002/food.19810250404

Cited by 7 publications

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“…It is a globular protein and its structure is stabilized by intramolecular interactions, such as disulfide bridges. Each monomer has two disulfide bridges and one free thiol group (Sienkiewicz, 1981a). The second most important whey protein is α–lactalbumin.…”

Section: Introductionmentioning

confidence: 99%

Effect of Sodium Sulfite, Sodium Dodecyl Sulfate, and Urea on the Molecular Interactions and Properties of Whey Protein Isolate-Based Films

et al. 2017

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Whey protein coatings and cast films are promising for use as food packaging materials. Ongoing research is endeavoring to reduce their permeability. The intention of this study was to evaluate the effect of the reactive additives sodium sulfite, sodium dodecyl sulfate (SDS), and urea on the oxygen barrier, water vapor barrier, and protein solubility of whey protein cast films. The concentration of the reactive additives was 1 to 20 wt.-%. Dried whey protein cast films were used as substrate materials. The water vapor transmission rate, the oxygen permeability, and the protein solubility were measured. Effective diffusion coefficients and effective sorption coefficients were calculated from the results of the water vapor sorption experiments. The presence of sodium sulfite resulted in an increased number of hydrophobic interactions and hydrogen bonds and a slightly decreased number of disulfide bonds. The oxygen permeability decreased from 68 to 46 cm3 (STP/standard temperature and pressure) 100 μm (m2 d bar)−1 for 1 wt.-% SDS in the whey protein cast film. The water vapor transmission rate decreased from 165 to 44 g 100 μm (m2 d)−1 measured at 50 to 0% r. h. for 20 wt.-% SDS in the whey protein cast film. The reduction in the water vapor transmission rate correlated with the lower effective diffusion coefficient.

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Section: Introductionmentioning

confidence: 99%

Effect of Sodium Sulfite, Sodium Dodecyl Sulfate, and Urea on the Molecular Interactions and Properties of Whey Protein Isolate-Based Films

et al. 2017

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“…Both main components of cow milk, a-Ltb (14.178 kDa, pI % 4.2-4.5 [25] ) and ß-Ltg (isoform A: M = 18.36 kDa; isoform B: M = 18.28 kDa; pI = 5.4 [26] ), were also included in the arsenic-binding studies. In the polypeptide chain of a-Ltb, four structure-forming disulfide bridges occur that give a globular structure to the protein.…”

Section: Rplc-esi-ms Analysis Of Interactions Of Pao With Peptides Anmentioning

confidence: 99%

Qualitative and quantitative characterization of the arsenic‐binding behaviour of sulfur‐containing peptides and proteins by the coupling of reversed phase liquid chromatography to electrospray ionization mass spectrometry

Schmidt

Mickein

2012

J. Mass. Spectrom.

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Phenylarsenic-substituted cysteine-containing peptides and proteins were completely differentiated from their unbound original forms by the coupling of reversed phase liquid chromatography with electrospray ionization mass spectrometry. The analysis of biomolecules possessing structure-stabilizing disulfide bridges after reduction provides new insights into requirements concerning the accessibility of cysteine residues for reducing agents as well as for arsenic compounds in a spatial protein structure. Complementary binding studies performed using direct ESI-MS without chromatographic coupling in different solvent systems demonstrated that more than one binding site were activated for aprotinin and lysozyme in denaturing solvents because of a stronger defolding. From the intensities of the different charge states occurring in the mass spectra as well as from the LC elution behaviour, it can be deduced that the folding state of the arsenic-bound protein species resembles the native, oxidized conformation. In contrast, although the milk protein α-lactalbumin has several disulfide bridges, only one phenylarsenic moiety was bound under strongly denaturing conditions. Because of the charge state distribution in the ESI mass spectra, a conformational change to a molten globule structure is assumed. For the second considered milk protein ß-lactoglobulin, a noncovalent interaction with phenylarsine oxide was detected. In general, smaller apparent binding constants for the condensation reactions of the biomolecules with phenylarsine oxide leading to covalent arsenic-sulfur bindings were determined from direct injection ESI-MS measurements than from LC-ESI-MS coupling. The following order of binding affinities for one phenylarsenic group can be assumed from both ESI-MS and LC-ESI-MS: nonapeptide vasopressin > nonapeptide vasotocin > lysozyme > aprotinin > α-lactalbumin > thioredoxin. Kinetic investigations by LC-ESI-MS yielded a partial reaction order of 2 for vasopressin, Lys and α-lactalbumin and corresponding half-lives of 0.93, 2.56 and 123.5 min, respectively.

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Nomenklatur und einige Eigenschaften der Molkenproteine. 2. Mitt. α‐Lactalbumin, Immunoglobuline, Proteose‐Peptone, Minorproteine und Enzyme

Sienkiewicz

1981

Nahrung

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Nomenklatur und einige Eigenschaften der Molkenproteine. 2. Mitt. a-Lactalbumin, Immunoglobuline, Proteose-Peptone, Minorproteine und Enzyme' T. SIENKIEWICZ Die Struktur und Funktion von r-Lactalbumin und von anderen Molkenproteinen werden diskutiert und einige Aspekte der thermischen Proteindenaturierung beschrieben. a-Lactaibamia AIIgemeines und Primarstruktur(ca. 1.3 g/l) ist das a-Lactalbumin (a-La) das nveitwichtigste Molkenprotein der Kuhmilch. Unter den Molkenproteinen der Humanmilch ist das a-La dem Gehalt nach (4,6 g/l) das bedeutendste Protein. Zur Reindarstellung von a-La konnen Fallungsverfahren [S. 841 oder physikalische Trennmethoden [45, 1091 eingesetzt werden. Fur einige Verwendungszwecke reicht es aus, ,,robes" I-La-Praparat durch Ammoniumsulfatdllung zu gewinnen und von Blutserumalbumin durch die Gelfiltration an Sephadex G-75 oder G-100 abzutrennen. Besonders reines Praparat (ohne Minorkomponenten) ist durch anschlieknde Ionenaustauschchromatographie an DEAE-Cellulose (bzw. DEAE-Sephadex) zu gewinnen 1591. Die Bezeichnung a-La wurde im Jahre 1930 von S J~R E N und SVEDBERG eingefuhrt fur das erste (a) in der Ultrazentrifuge sedimentierendes Protein aus der durch Auskristallisieren aus lMolke gewomnen Albuminfraktion. Das a-La ist durch die Sgttigung der Molke mit Magnesiumsulfat nicht Gllbar. Die vollstandige Aminosiiuresequenz von a-La wurde von BREW u. a. [25] aufgeklgrt. Das in der Kuhmilch auftretende monomere Protein mit einer relativen Molekiilmasse von 14 176 besteht aus 123 Aminosiiuren und besitzt vier Cystin-und keine Cysteinreste. Weitere charakteristische Merkmale sind: Gesamtstickstoffgehalt von 15.86 %, der hochste Tryptophangehalt von allen bekannten natiirlichen Proteinen (6,9 g/100 g Protein) und ein hohes Verhaltnis von polaren zu nichtpolaren Aminosauren. Der Gehalt von essentiellen Aminosauren ist hoch. der prozentuelle Absorbtionskoeffizient A: : ': bei 280 nm Wellenlange des UV-Lichtes 20.1 bzw. 20,6 [70, IOO]. Gegenwartig ist r-La bei 13 Tierarten gefunden, isoliert und charakterisiert worden [MI. Von Rinder-a-La 1261, Human-a-La [44] und Meerschweinchen-@-La [23j sind die vollstandigen Aminosiiuresequenzen bekannt. Teilsequenzen wurden von vier weiteren a-La ermittelt 1641. z-La kommt in allen Milcharten, die Lactose enthalten, vor. Am Beispiel von 6 Tierarten zeigten LEY u. a. [75], daD zwischen a h -und Lactosegehalt eine positive Korrelation besteht. Dies ist nicht iiberraschend, seitdem bekannt ist, daO das a-La das ,,B"-Protein eines Enzyms ist, niimlich der Lactose-Synthetase [40], Mit einem Gehalt bis zu 25 I. Mitt. Nahrung, 25, 329 (1981).

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Nomenklatur und einige Eigenschaften der Molkenproteine. 1. Mitt. β‐Lactoglobulin

Abstract: In einer Übersicht werden gemeinsame Merkmale der Molkenproteine dargestellt. Die Struktur und die Funktion von β‐Lactoglobulin sowie einige Aspekte der thermischen Proteindenaturierung werden beschrieben.

Cited by 7 publications

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Effect of Sodium Sulfite, Sodium Dodecyl Sulfate, and Urea on the Molecular Interactions and Properties of Whey Protein Isolate-Based Films

Effect of Sodium Sulfite, Sodium Dodecyl Sulfate, and Urea on the Molecular Interactions and Properties of Whey Protein Isolate-Based Films

Qualitative and quantitative characterization of the arsenic‐binding behaviour of sulfur‐containing peptides and proteins by the coupling of reversed phase liquid chromatography to electrospray ionization mass spectrometry

Nomenklatur und einige Eigenschaften der Molkenproteine. 2. Mitt. α‐Lactalbumin, Immunoglobuline, Proteose‐Peptone, Minorproteine und Enzyme

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