Isolation of the 12 S globulin from Rapeseed (Brassica napus L.) and characterization as a “neutral” protein On seed proteins. Part 13

✍ Scribed by Schwenke, K. D. ;Raab, B. ;Linow, K.-J. ;Pahtz, W. ;Uhlig, J.

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 543 KB
• Volume: 25
• Category: Article
• ISSN: 0027-769X
• DOI: 10.1002/food.19810250307

✦ Synopsis

Abstract

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 (I Glu, Asp — Amide ammonia: ∑ 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.).