An isolation procedure for the 12 S rapeseed globulin is described which includes precipitation by dialysis, purification using gel chromatography on Sephadex G-200, and ion-exchange chromatography on DEAE-Sephadex A-50. The isolated globulin represents a neutral protein with an isoelectric point at pH 7.25--determined by isoelectric focusing--and a relation of the acidic to basic amino acid residues (epsilon Glu, Asp--Amide ammonia: epsilon Arg, Lys, His) of 1.0. As in other storage globulins high contents of glutamic (19%) and aspartic (10%) acid and a low content of sulphur containing amino acids are characteristic for the amino acid composition. Amongst the basic amino acids arginine has the highest percentage (7%). Opposite to results of other authors the sugar content of the globulin is low (0.5%). From the amino acid composition an average hydrophobicity according to Bigelow was calculated which amounts to be 1041 cal/res. (4.36 kJ/res.).

An improved procedure for the isolation and purification of the 11 S globulin from sunflower seeds (helianthinin) is described, including a combined purification by gel chromatography and ionexchange chromatoThe protein has a sedimentation constant of szo, = 12.8 x lo-'' s, a STOKES radius of 57 A and a diffusion constant of 3.76 x lo-' cm2 s-' (the last two derived from gel chromatographic analysis). Hence it follows a molecular weight of M, = 305000. The isoelectric point determined by isoelectric focusing lies at pH 4.7.High contents of glutamic (26%) and aspartic (14%) acid and arginine (9.7 %) as well as a low content of sulphur containing amino acids are characteristic for the amino acid composition. 59 % of the acidic amino acids are present in an amidated form. The globulin contains 12 disulphide bridges per molecule. graphy.Helianthinin is the main storage protein in sunflower seed [l]. It represents a typical 11 S globulin with a molecular weight near 300000, dissociation properties depending on pH and ionic strength, a low content of a-helix, a relatively high amount of p-conformation, and a high content of arginine, glutamic and aspartic acid (2-51. In the present paper an improved purification for the globulin combining gel filtration and ion-exchange chromatography, the corrected amino acid composition, the content of amide-nitrogen and SS/SHgroups, and some physico-chemical properties of the globulin are described. Material and Methods Protein isolationGround dehulled sunflower seeds were defatted with diethyl ether and extracted with a 5% solution of sodium chloride in a cold room. The protein was precipitated with cold water and twice chromatographed on Sephadex G-200 as described in a previous paper [6].

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Ein aus Legumin und Vicilin bestehendes Rohglobulinpriiparat aus Ackerbohnen ( Viciafubu L.) dissoziiert nach Succinylierung der Aminogruppen in Untereinheiten, die sedimentationsanalytisch als 2.84-Fraktion erscheinen. Gelelektrophoretisch lassen sich bereits in Modifikaten mit einem Succinylierungsgrad von 37 Y, die assoziierten F'roteine nicht mehr nachweisen, die Proteinmuster hochgradig succinylierter Proben weisen mindestens 6 Zonen auf.Die pH-Liislichkeitsprofle der succinylierten Proteine zeigen eine vom Succinylierungsgrad abhangige Verschiebung des Loslichkeitsminimums nach niedrigeren pH-Werten und eine Herabsetzung der Liislichkeit bei pH-Werten < 4.MiiDig (27Xig) modifizierte Proteine zeigen eine Zunahme der Wasserbindung um 25% und der albindung um 40". Eki stslrker succinylierten Proben sinkt das 6lbindevermogen auf 80 bis 60% des Kontrollwertes. Die Emulgiereigenschaften (Emulgierkapazitat. Emulgieraktivitlt, Emulsionsstabilitat) der Ackerbohnenproteine lassen sich durch Succinylierung wesentlich verbessern.In einer vorangegangenen Mitteilung ist iiber die physikochemischen und funktionellen Eigenschaften succinylierter Caseinproben berichtet worden [2]. Gegenstand der vorliegen: den Arbeit sind analoge Untersuchungen an verschieden stark succinylierten Proben eines Proteinisolates aus Ackerbohnen ( Viciu .fubu L.). Material und Methoden ProteinisolirrungEs wurden Ackerbohnen der Sorte Fribo in kner Schillmiihle geschiilt und gemahlen. Die Proteinextraktion erfolgte durch 2 min Homogenisieren (Ultraturrax -Homogenisator) von 80 g Samenmehl mit 800 mi Wasser bei knem pH-Wert von 8.0-8.5. Aus dem klarzentrifugierten Extrakt wurde die Globulin-Frdktion durch Zugabe von Salzsiiure bei einem pH-Wen von 4,5 isoelektrisch ausgeWllt. Nach mehrmaligem Waschen wurde das Globulin-Praparat gefriergetrocknet.

The chemical and physicochemical changes of the low‐molecular weight basic albumin fraction from rapeseed, as a function of degree of acetylation, were studied using amino and ester groups analyses, PAGE electrophoresis, isoelectric focusing, viscometry, circular dichroism and fluorescence spectroscopy. The surface hydrophobicity was evaluated by means of the ANS fluorescence probe technique. The protein was readily acetylated at the amino groups by addition of acetic anhydride. Acetylation of amino acid hydroxyl groups was significantly slower and proceeded in the presence of an excess of the reagent after the amino groups had already been blocked. Acetylation resulted in protein species with isoelectric points at pH 7.6, 6.6, 5.95 and 5.4. The intrinsic viscosity of the native protein fraction dropped from 0.159 dlg−1 to 0.038 dlg−1 at a moderate degree of modification. The secondary structure of the protein, characterized by a content of 40–45% helix conformation, was not significantly influenced by acetylation. Modification did not result in wavelength shifts of the peaks in the near ultraviolet CD and fluorescence spectra. However, the negative ellipticities in the 250–270 nm region of the CD spectrum increased markedly with increasing degree of acetylation. The surface hydrophobicity increased linearly with the amount of acetyl groups introduced into the protein.