Über Samenproteine. 4. Mitt. Isolierung der Globulin‐Hauptkomponente aus Sonnenblumensamen

Abstract

Es wird die Isolierung des sedimentationsanalytisch und gelchromatographisch einheitlichen 11‐S‐Globulins aus Sonnenblumensamen aus 10% Natriumchlorid enthaltenden Extrakten mit Hilfe einer Fällung mit Wasser und nachfolgender wiederholter Chromatographie des albuminfreien Rohglobulins an Sephadex G‐200 beschrieben. Mit der gleichen Verfahrensweise gelingt die Isolierung einer in geringen Mengen anwesenden 7‐S‐Komponente. Die Sedimentationskonstante s20,w des 11‐S‐Globulins beträgt 11,8 S. In Lösungen niedriger Ionenstärke (I ≤ 0,3) dissoziiert das Protein in eine 7‐S‐Komponente. Bei der Gelelektrophorese in Aluminiumlactat‐Puffer vom pH 3,1 erscheint das 11‐S‐Globulin ebenfalls mit der 7‐S‐Komponente als Dissoziationsprodukt vergesellschaftet. Letztere ist elektrophoretisch mit der gelchromatographisch isolierten 7‐S‐Komponente identisch. Die Aminosäurenzusammensetzung des 11‐S‐Globulins ist durch einen hohen Gehalt an Glutamin‐ und Asparaginsäure, Arginin, Leucin, Phenylalanin, Valin und Isoleucin gekennzeichnet. Die biologische Wertigkeit nach Oser beträgt 73. Lysin und die schwefelhaltigen Aminosäuren sind limitierend.

On seed proteins Part 11. Purification, Chemical Composition, and Some Physico‐chemical Properties of the 11 S Globulin (Helianthinin) in Sunflower Seed

“…According to the dissociation of the helianthinin depending on the ionic strength we predicted the appearance of at least two components during the ionexchange chromatography using a salt gradient [2]. As the present results show, the 7 S component as the product of dissociation appears, indeed, during the elution of the protein from the DEAESephadex column at an ionic strength -0.4 in fraction A.…”

“…In order to get a homogeneous 11 S giobulin by purification of the raw globulin on the ion-exchange column without any preliminary purification by gel chromatography, the cryoprecipitated protein [2] was brought directly onto the DEAE-Sephadex column. Molecular weight and some hydrodynamic properties Fig.…”

Sunflower proteins: overview of their physicochemical, structural and functional properties

“…Nevertheless, various amounts of proteins with 7S sedimentation coefficient have been detected in sunflower seeds 48, 50, 54. These 7S constituents are most likely dissociation products of the 11S globulins, a dissociation which also occurs in soybean glycinin 8, 108–111. Furthermore, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) did not show differences between the molecular subunits of the 11S and 7S forms of sunflower globulins under both reducing and non‐reducing conditions 111…”

“…According to Molina et al ,127 helianthinin shows a hexameric form at pH 6–9 (ionic strength ( I ) = 500 mmol L −1 ). It has been reported that in solutions of low ionic strength ( I < 300 mmol L −1 ) the 11S form of helianthinin dissociates into the 7S form (pH 7–8) 108, 129. However, González‐Pérez et al 111 demonstrated that both forms of helianthinin (11S and 7S) are present at near neutral pH over a broad ionic strength range (30–1250 mmol L −1 ), although a higher ionic strength contributes to stabilisation of the 11S form.…”

Hydrodynamic and Quasi‐elastic Light Scattering Studies on the 12s Globulin From Rapeseed*

“…In the case of the 11s globulin from sunflower seed we were able to show that in solutions of low ionic strength a dissociation of the 11s protein with a molecular weight of 305,000 takes place to form 7 s half molecules with a molecular weight of 150,000 (Schwenke et al, 1974;Behlke & Schwenke, 1976). The experimental conditions of determination of the molecular weight of the rapeseed globulin were not published by Gill & Tung (1976) but the poor solubility of their protein prep aration points to a strong aggregation during the freeze-drying process.…”