Three albumins were isolated from bread wheat seeds by gelfiltration on Sephadex G-100 and differential preparative disc-electrophoresis on polyacrylamide gel. The proteins were obtained in suficient yield and purity to carry out characterisation studies. The electrophoretic mobilities of the three albumins in polyacrylamide discs in glycine- Tris medium, p H 9.5, were 0.28, 0.34 and 0.39 (referred to that of bromophenol blue taken as I ) . The isoelectric points were 6'40, 6.40 and 5.35 and the molecular weights 17,700,18,200 and 18,900, respectively. The amino acid compositions o f the purified albumins were very similar. The correlation of the purified albumins with those isolated from bread wheats by other authors is discussed. Introduction'SOLUBLE' proteins from bread and Triticum durum wheat are usually separated using electrophoretic m e t h o d~. l -~ However, the heterogeneity of protein extracts, even after a preliminary fractionation, seriously limits the evaluation of these results. Therefore, attempts were made to extract and purify species-specific proteins from, for instance, bread wheat in order to prepare immune sera against the proteins. Several varieties of both species could then be tested by immunodiffusion and the specificity of such fractions could be statistically analysed. In this way it was possible to characterise an albumin specific for bread wheat.10-12The albumin fraction from the seeds of Triticum aestivum or Triticum durum, extracted with 0. S M -N~C~ and precipitated with between 0 . 9 3~ and 1.33 M ammonium sulphate, was gelfiltered on Sephadex G-100. Four major fractions of different molecular weights were obtained (A, B, C, D) (Cantagalli, P., unpublished results). In disc-electrophoresis the lowest molecular weight fraction (Db) from bread wheat had a significantly different composition from the same fraction obtained from T. durum wheat (Dd) (Cantagalli, P., unpublished results).Therefore, an attempt was made to isolate and characterise the albumins present in fraction D b . Experimental Extraction and purification of albuminsAlbumins were extracted according to the method of Cantagalli et a1.13 1000 g of bread wheat whole flour (a mixture of varieties Autonomia and Generoso) were suspended in 2000 ml of phosphate buffer, pH 6.6 ( O -O~~M M -N~~H P O~, O .~~I M -K & P O~, 0-48~-NaCi), at 4"c and left overnight. The suspension was then centrifuged at 2700 Y g and the albumins were separated from the supernatant by salting out with between 0 . 9 3~ and 1 ' 33111 ammonium sulphate. The precipitate obtained was collected by centrifuging at 2700 x g and washed three times with 1 *33M ammonium sulphate. The yield of albumins was approximately 1 g. Gel-filtration on SephadexAbout 1 g of albumins was dissolved in 25 ml of buffer solution, pH 7.4 (0.008~-NazHP04, 0.001rvr-KH2P04, 0.137~-NaC1, 0*003~-KC1), applied on a Sephadex G-100 column (90 x 6 cm) and eluted with the same buffer at a rate of 1 .O ml/min, according to the method of Cantagalli et al.13 * Laboratorio Chimico Pro...