Biochemical and Spectroscopic Characterization of Almond and Cashew Nut Seed 11S Legumins, Amandin and Anacardein

Abstract

Native, undenatured amandin and anacardein secondary structures were estimated to be, respectively, 56.4 and 49% β-sheet, 14 and 23.7% α-helix, and 29.6 and 27.4% random coil. Circular dichroic (CD) and fluorescence spectroscopy were used to assess structural changes in amandin and anacardein subjected to denaturing treatments that included heat (100 °C, 5 min), guanidium HCl (GuHCl), urea, sodium dodecyl sulfate (SDS), and reducing agent, 2% v/v β-mercaptoethanol (βME) + heat. Mouse monoclonal antibodies (mAbs) 4C10 and 4F10 directed against amandin and 1F5 and 4C3 directed against anacardein were used to assess the influence of denaturing treatments on the immunoreactivity of amandin and anacardein. Among the denaturing treatments investigated, SDS and β-ME caused a significant reduction in the immunoreactivity of amandin and anacardein when probed with mAb 4C10 and 4C3, respectively.

Purification and biochemical characterization of 11S globulin from chan (Hyptis suaveolens L. Poit) seeds

“…1A), that corresponds to the typical molecular weight range reported for the 11S globulin monomers (Tandang-Silvas et al, 2011). In R-SDS-PAGE these bands are reduced generating the a ($27-30 kDa) and b ($18-24 kDa) subunits, confirming the presence of a disulfide bond highly conserved among legumins (Kshirsagar et al, 2011;Tandang-Silvas et al, 2011). Two main peaks resulted after total globulin extract passed through Sephacryl S-200 SEC under native conditions (data not shown).…”

“…Legumins are the most extensively studied seed storage proteins, because they are the most widely distributed in nature, being present in both monocot and dicotyledonous seeds (Shewry et al, 1995;Tandang-Silvas et al, 2011). The 11S globulins are hexameric proteins of 275-450 kDa and have 50-60 kDa monomers, which are composed of an acidic (a) subunit (30-40 kDa) and a basic (b) subunit (20-25 kDa) linked by a single disulfide bond highly conserved among plant legumins (Kshirsagar, Fajer, Sharma, Roux, & Sathe, 2011;Tandang-Silvas et al, 2011). The 11S globulin monomers are synthesized as a single precursor protein, from which the signal sequence is separated co-translationally.…”

Immunoreactivity of Biochemically Purified Amandin from Thermally Processed Almonds (Prunus dulcis L.)

“…In addition, purified tropomyosin from boiled shrimp had higher IgE-binding capacity than tropomyosin purifed from the raw counterpart (Liu et al, 2010). Partial opening of amandin structure after heating was previously observed by Kshirsagar, Fajer, Sharma, Roux, and Sathe (2011) Values are means ± standard error of means. R value = ratio of concentration at 50% maximum signal for processed to unprocessed, n = 3 each.…”

“…In addition, purified tropomyosin from boiled shrimp had higher IgE‐binding capacity than tropomyosin purifed from the raw counterpart (Liu et al., ). Partial opening of amandin structure after heating was previously observed by Kshirsagar, Fajer, Sharma, Roux, and Sathe () when flourescence quenching was used to assess structural changes in purified amandin subjected to thermal denaturation (boiling water bath, 100 °C, 10 min). Accessability of tryptophan flourophores to acrylamide quencher significantly increased (105.6%) compared to the control (67.4%) indicating improved exposure of buried epitopes upon thermal treatment.…”

A review of the impact of processing on nutrient bioaccessibility and digestion of almonds

“…The major storage protein found in almonds, sometimes called amandin or almond major protein, belongs to the legumin class of seed proteins, which itself is a part of the globulin family (Osborne & Campbell, 1896;Kshirsagar et al, 2011). Globulin proteins are classified according to their sedimentation coefficient, with the legumin type being 11S.…”