Chicken ovomucoid

Bowman-Birk inhibitor [7,141,145], camostat mesilate (=FOY-305) [3,5,76], chicken ovoinhibitor [47], chicken ovomucoid [46], DFP [26], flavonoid inhibitors [149], human pancreatic trypsin inhibitor [48], leupeptin [3], p-aminobenzamidine [150], PMSF [151], poly(acrylate) derivatives [152], soybean trypsin inhibitor [5,7,46,51,78,141], TLCK (tosyllysine chloromethlyketone) [26]... 

Further inhibitors of this class are the chicken egg white trypsin inhibitor (= chicken ovomucoid 186 amino acids) [46], the chicken ovoinhibitor (449 amino acids) [47], and the human pancreatic trypsin inhibitor (56 amino acids), which can already be produced in Escherichia coli [48]. 

Trypsin j>-Aminobenzamidine, antipain, aprotinin, Bowman-Birk inhibitor, camostat mesylate, chicken ovoinhibitor, chicken ovomucoid, human pancreatic trypsin inhibitor, soybean trypsin inhibitor,... 

Bernhisel-Broadbent, J., Dintzis, H.M., Dintzis, R.Z., Sampson, H.A. 1994. Allergenicity and antigenicity of chicken egg ovomucoid (Gal d III) compared with ovalbumin (Gal d I) in children with egg allergy and in mice. J Allergy Clin Immunol 93 1047-1059. 

Holen, E., Bolann, B., Elsayed, S. 2001. Novel B and T cell epitopes of chicken ovomucoid (Gal d 1) induce T cell secretion of IL-6, IL-13, and IFN-gamma. Clin Exp Allergy 31 952-964. 

Kato, I., Schrode, J., Kohr, W.J., Lakowski, M. Jr. 1987. Chicken ovomucoid Determination of its amino acid sequence, determination of the trypsin reactive site, and preparation of all three of its domains. Biochemistry 26 193-201. 

Rupa, P., Hamilton, K., Cirinna, M., Wilkie, B.N. 2007. A neonatal swine model of allergy induced by the major food allergen chicken ovomucoid (Gal d 1). Int Arch Allergy Immunol 146 11-18. 

Chicken ovomucoid has an arginine at the reactive site and therefore no essential amino group. 

There are examples of inhibitors which are specific for only one protease within a group. The best known examples Include the Kunitz soybean (Glycine max) inhibitor (14) and isoinhibitors I and II of the Great Northern bean (Phaseolus vulgaris)(15). Even these two examples are not clear cut as there is some small non-stoichiometric combination and inhibition of a-chymotrypsin. Chicken (16) and Japanese quail (17) egg white ovomucoids only inhibit trypsin. 

They are proteins of 28,000 daltons and contain 20% carbohydrate. They are quite similar in other properties as well. However, they can be quite different in their inhibitory properties against proteases. Chicken (16) and Japanese quail (17) ovomucoids inhibit only trypsin. Tinamou ovomucoid inhibits chymotryp-sin and subtilisin (66) and turkey ( 67) and penguin ( 68) ovomucoids inhibit trypsin, chymotrypsin and subtilisin. The reason for this difference among the ovomucoids is due to more than one binding site for proteases in the ovomucoid molecule. As shown by... 

There appears to be sequence homology between the pineapple stem bromelain inhibitors and some of the small molecular weight inhibitors from the legumlnosae (91) Human inter-a-trypsin inhibitor contains two domains with great similarity to the domains of the Kunitz-type inhibitors (44 92-94)> The ovoinhibitors from Japanese quail and chicken egg whites contain six tandem domains which are homologous to the Kazal pancreatic secretory inhibitor and to the ovomucoids (69) ... 

The inhibitors from chicken egg white, ovomucoid and ovoinhib-itor, show similar stabilities by inactivation (see Refs, to Table II) or DSC criteria (Donovan and Beardslee, 1975 Zahnley, 1979). 

Many enzymes or other proteins are stabilized by interaction with small ligands (substrates, cofactors, inhibitors, products). Nonspecific protection by macromolecules and stabilization by specific protein—protein interaction are generally less readily quantified. As a model system in which to determine effects of protein—protein interaction on conformational (thermal) stability, Donovan and Beardslee (1975) selected the proteinase—inhibitor association between bovine 3-trypsin and STI or chicken ovomucoid. They observed that both protein components were stabilized in the 1 1 complexes and, furthermore, that each trypsin—inhibitor complex showed one endotherm in the DSC. No stabilization was observed for a weaker electrostatic complex between ovalbumin andjysozyme. They interpreted the stabilization as an increase in kinetic thermal stability, i.e., a decrease in the rate of denaturation at a given temperature. Results obtained by other methods (Edelhoch and Steiner, 1965 Laskowski and Sealock, 1971 Jibson et al., 1981) show that proteinase—inhibitor association generally involves no major conformational changes in the proteins. 

Two non-inhibitory proteinase—proteinase inhibitor combinations exhibit destabilization of inhibitor proteins in the DSC (Zahnley, unpublished). Ovoinhibitor was rapidly degraded by thermolysin, as indicated by decreases in both T(j and area (AHd) of its endotherm. Chicken ovomucoid was slowly degraded by proteinase K (Fig. 9), a fungal serine proteinase that attacks many native proteins. Proteinase K, in accord with its subtilisin-1ike specificity (Kraus and Femfert, 1976), was inhibited by chicken ovoinhibitor, but not by chicken ovomucoid. In these non-inhibited systems, proteolysis can destabilize the inhibitor (substrate) protein, provided the susceptible bonds are accessible to the proteinase. Relevance of these examples to food systems derives from the role of proteolysis in protein deterioration (Feeney, 1980) and digestion. 

Figure 8. Stabilization of proteinases (aT ) on association with their protein inhibitors as a function of the logarithms of the equilibrium association constants (log K ssoc). Horizontal bar lines are used to indicate the range of log Kassoc values. Key to inhibitors (inside Figure, at lower right) OM, chicken ovomucoid for other abbreviations, see Table II. Key to proteinases BT, bovine p-trypsin PT, porcine 6-trypsin ...

Figure 9. Time course of thermal destabilization of chicken ovomucoid (OM) by treatment (proteolysis) with proteinase K (PrK).

LBI (Fraenkel-Conrat et al., 1952), proteinase inhibitor II from potato (Bryant et al., 1976 Huang et al., 1981) and chicken ovomucoid (see below). Substantial differences in stability have been reported for STI (Ellenrieder et al., 1980), trypsin-chymotrypsin inhibitor from chick pea (Belew et al., 1975), inhibitors from some other beans (Sgarbieri and Whitaker, 1982), peanut trypsin inhibitor (Tur-Sinai et al., 1972 Perkins and Toledo, 1982), proteinase inhibitor I from potato (Ryan, 1966 Huang et al., 1981), and chicken ovoinhibitor (see below). Although stabilities of the crude and purified inhibitors may differ, characterization of intrinsic stability requires isolation of the inhibitor protein. Effects of other factors on stability of the crude inhibitor may be difficult to define. 

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