Stability of the allergenic soybean Kunitz trypsin inhibitor

Abstract

The soybean Kunitz trypsin inhibitor (SKTI) is a 21.5 kDa allergenic protein that belongs to the family of all antiparallel h-sheet proteins that are highly resistant to thermal and chemical denaturation. Spectroscopic and biochemical techniques such as circular dichroism (CD), ANS fluorescence and proteolysis were used to study its molecular structure under denaturing conditions such as acid and heat to which these allergens are commonly exposed during food processing. Reduction of native SKTI leads to its complete and rapid proteolysis by pepsin in simulated gastric fluid (SGF). Limited proteolysis with chymotrypsin during renaturation after heating showed that the native structure reforms at around 60 jC reversing the denaturation. CD spectra revealed that under acid denaturing conditions, SKTI shows major changes in conformation, indicating the possibility of a molten structure. The existence of this intermediate was established by ANS fluorescence studies at different concentrations of HCl. The remarkable stability of SKTI to both thermal and acid denaturation may be important for its role as a food allergen. D

Effects of food processing on food allergens

“…The results suggested that IgE reactivity of rAra h 2 increased, thus confirming the earlier observations of Maleki et al [30]. Roychaudhuri et al [32] have shown that soybean Kunitz trypsin inhibitor is a 21.5 kDa allergenic protein that belongs to a family of all antiparallel b-sheet proteins that are highly resistant to thermal and chemical denaturation.…”

Effects of Dietary Soybean Trypsin Inhibitors on Detection of Resistance to Pyrethroid and Spinosad Insecticides in Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

“…KSTI is highly resistant to thermal and acidic denaturation (Roychaudhuri, 2003). Thus any resistance to xenobiotics that is conferred by enhanced serine hydrolases (i.e.…”

Review Soybeans as bioreactors for biopharmaceuticals and industrial proteins

“…For the latter, the 15S fraction corresponds to 1% of the globulins, has a high molecular mass (700 kDa) and has an isoelectric point of 4.5. Furthermore, the known proteins in soybean seeds with high allergenic potential are mainly composed of a 34-kDa maturing seed protein (also known as P34, Gly m Bd 30 K or Gly m 1) (Sewekow et al, 2008), the 23-kDa protein Gly m Bd 28 K (Xiang et al, 2004), β-conglycinin (Krishnan et al, 2009), the glycinin Gly m 6 (Holzhauser et al, 2009), lectin andlypoxygenase (L'Hocine andBoye, 2007), and a Kunitztype protease inhibitor (Roychaudhuri et al, 2004). There are also some allergenic proteins in seed shell, such as Gly m 1.0101, Gly m 1.0102, Gly m 2, Gly m 3, and SAM 22 (Gly m 4).…”