2S albumins

S albumins are highly allergic, small molecule storage proteins present in many seeds, such as sesame, castor bean, sunflower, oriental and yellow mustard, as well as in Brazil nuts and walnuts (Pastorello et al., 2001). 

The 2S albumin family is an important class of common allergenic proteins in seeds. Their presence in almost all edible seeds must be taken into account because of the high incidence of possible clinical reactions occurring in sensitized people and because of the actual possibility of cross-reactivity among different proteins of the same class. 

Many allergenic 2S albumins originate from the Brassicaceae family, i.e., oriental mustard seed Bra j 1, rapeseed Bra n 1, turnip Bra r 1, and yellow mustard seed Sin a 1. Furthermore, Brazil nut Ber e 1, black walnut Jug n 1, Jug r 1, and Jug r 4 from English walnut, Ses i 1 and Ses i 2 from sesame, Ric c 1 from castor bean, Ana o 3 from cashew nut, and Pis v 1 from pistachio have been included into the IUIS official allergen fist. 

Koppelman, S.J., Nieuwenhuizen, W.F., Gaspari, M. et al. 2005. Reversible denaturation of Brazil nut 2S albumin (Ber el) and implication of structural destabilization on digestion by pepsin. JAgric Food Chem 53 123-131. 

Pastorello, E.A., et al. (2001). Lipid transfer proteins and 2S albumins as allergens. 

Lehmann, K., Schweimer, K., Neudecker, P., and Rosch, P. 2004. Sequence-specific 1H, 13C and 15N resonance assignments of Ara h 6, an allergenic 2S albumin from peanut. JBiomolNMR 29 93-94. 

Other therapeutic proteins produced in plants include leuenkephalin, a neuropeptide produced in B. napus and Arabidopsis as part of the seed storage protein 2S albumin. The peptide was proteolytically cleaved from the storage protein and recovered by high-performance liquid chromatography (HPLC). In addition, a biologically active form of the human 

Clement, G., Boquet, D., Mondoulet, L., Lamourette, R, Bernard, H, and Wal. J.M. 2005. Expression in Escherichia coli and disulfide bridge mapping of PSC33, an allergenic 2S albumin from peanut. Protein Expr Purif44(2) 110-120. 

Burnett GR, Rigby NM, Clare Mills EN, et al. Characterization of the emulsiOcation properties of 2S albumins from sunflower seed. J Colloid Interface Sci 2002 247(1) 177-185. 

Allergenic storage proteins of 2S type are also most likely to be responsible for cross-reactivity between nuts and sesame seeds. Sesame seeds contain ca. 20% protein of which 2S albumins make almost a quarter (Rajendran and Prakash 1988). 

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