Cor a 9
Sterile Filtered clear solution.
Greater than 80.0% as determined by SDS-PAGE.
Description
The native protein Corylus Avellana Cor a 9 is purified from hazelnut by protein chemical methods.
Product Specs
Cor a 9, classified as an 11S legumin-like seed storage globulin, is a primary allergen found in Corylus avellana (hazelnut). It is known to trigger severe systemic allergic reactions. Identifying sensitization to Cor a 9 is crucial for diagnosing primary hazelnut allergy.
The protein, Corylus Avellana Cor a 9, is extracted from hazelnuts and purified using specialized protein chemical methods.
The product is a clear solution that has been sterilized through filtration.
Cor a 9 is provided in a buffer solution of 20mM HEPES (pH 8.0), 200mM NaCl, and 20% glycerol.
For short-term storage (2-4 weeks), the vial can be stored at 4°C. For extended storage, it is recommended to freeze the product at -20°C. To maintain product integrity, avoid repeated freezing and thawing.
The purity of the product is greater than 80.0%, as determined by SDS-PAGE analysis.
This product serves two primary immunological functions: 1) It can bind to human IgE antibodies, and 2) It can be utilized in immunodot tests to differentiate between positive and negative samples.
This product has undergone testing using the LAL (Limulus Amoebocyte Lysate) chromogenic endotoxin assay.
Product Science Overview
Corylus avellana, commonly known as the common hazel, is a species of flowering plant in the birch family Betulaceae. It is native to Europe and Western Asia and is an important component of hedgerows historically used as property and field boundaries in lowland England . The plant is typically a shrub reaching 3 to 8 meters in height, but it can grow up to 15 meters in some cases . The leaves are deciduous, rounded, and softly hairy on both surfaces, with a double-serrate margin . The flowers are produced very early in spring, before the leaves, and are monoecious with single-sex wind-pollinated catkins .
The fruit of Corylus avellana is a nut, commonly known as a hazelnut or cob nut, which is edible and used raw, roasted, or ground into a paste . The nut is roughly spherical to oval, yellow-brown with a pale scar at the base, and falls out of the involucre when ripe .
Cor a 9 is a thermoresistant storage protein of the 11S globulin family found in hazelnut (Corylus avellana) . It is a major allergen and is associated with severe systemic reactions . The allergenic acidic polypeptide chain of Cor a 9 possesses a molecular weight of 40 kDa . Sensitization to Cor a 9 indicates primary hazelnut allergy and is more prevalent in children than in adults .
Cor a 9 has two important features: its ability to induce direct (primary) sensitization to hazelnut, as opposed to pollen-related sensitization, and its association with more severe clinical reactions such as skin, respiratory, gastrointestinal, or even anaphylaxis . Determination of specific immunoglobulin E (sIgE) for Cor a 9 can serve as a predictive marker for clinical allergy to hazelnut with severe symptoms . However, the predictive ability of Cor a 9-sIgE is lower than that of Cor a 14-sIgE .
Despite high sequence homology with several other 11S globulins, such as those found in walnut, mustard, soybean, peanut, Brazil nut, almond, cashew nut, and pistachio, clinical cross-reactivity may not be present . Co-sensitization of Cor a 9 has been reported with 11S globulins like Jug r 4 (walnut) and Sin a 2 (mustard) as well as with 2S albumins like Jug r 1 and Ana o 2 (cashew nut) .
Hazelnut allergy, particularly to Corylus avellana, is the most common tree nut allergy in Europe . According to a systematic review, this allergy accounts for about 17% to 100% of the total tree nut allergies in Europe . Sensitization to Cor a 9 among hazelnut-sensitized individuals has been described in Central, Southern, and North-Western Europe as well as in the United States . The EuroPrevall study conducted from 2005 to 2010 among 731 hazelnut-sensitized individuals in 12 European centers reported an overall prevalence of 9.9% for sensitization to Cor a 9 .
