Ovomucoid: Difference between revisions – Wikipedia

 

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”’Ovomucoid”’ is a [[protein]] found in [[egg white]]s. Ovomucoid’s main source is in various avian species like chickens ”(Gallus gallus domesticus)” and ducks ”(Anatidae)” and makes up approximately 11% of proteins<ref>{{Cite web |title=Ovomucoid – an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/ovomucoid#:~:text=Ovomucoid |access-date=2025-11-24 |website=www.sciencedirect.com}}</ref> found in egg whites.

”’Ovomucoid”’ is a [[protein]] found in [[egg white]]s. Ovomucoid’s main source is in various avian species like chickens ”(Gallus gallus domesticus)” and ducks ”(Anatidae)” and makes up approximately 11% of proteins<ref>{{Cite web |title=Ovomucoid – an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/ovomucoid#:~:text=Ovomucoid |access-date=2025-11-24 |website=www.sciencedirect.com}}</ref> found in egg whites.

t is a [[trypsin inhibitor]] with three [[protein domain]]s of the [[Kazal domain]] [[protein family|family]].<ref name=”Lineweaver_1947″>{{cite journal | vauthors = Lineweaver H, Murray CW | title = Identification of the trypsin inhibitor of egg white with ovomucoid | journal = The Journal of Biological Chemistry | volume = 171 | issue = 2 | pages = 565–581 | date = December 1947 | pmid = 20272096 | doi = 10.1016/S0021-9258(17)41067-2 | doi-access = free }}</ref><ref name=”Rimphanitchayakit_2010″>{{cite journal | vauthors = Rimphanitchayakit V, Tassanakajon A | title = Structure and function of invertebrate Kazal-type serine proteinase inhibitors | journal = Developmental and Comparative Immunology | volume = 34 | issue = 4 | pages = 377–386 | date = April 2010 | pmid = 19995574 | doi = 10.1016/j.dci.2009.12.004 | bibcode = 2010DCImm..34..377R }}</ref> The [[homology (biology)|homolog]]s from [[chicken]]s (”Gallus gallus”) and especially [[turkey (bird)|turkeys]] (”Meleagris gallopavo”) are best characterized. It is not related to the similarly named [[ovomucin]], another egg white protein. Chicken ovomucoid, also known as ”’Gal d 1”’, is a known [[allergen]]. It is the protein most often causing [[egg allergy]]. At least four [[IgE]] [[epitope]]s have been identified.<ref name=”Jarvinen_2007″>{{cite journal | vauthors = Järvinen KM, Beyer K, Vila L, Bardina L, Mishoe M, Sampson HA | title = Specificity of IgE antibodies to sequential epitopes of hen’s egg ovomucoid as a marker for persistence of egg allergy | journal = Allergy | volume = 62 | issue = 7 | pages = 758–765 | date = July 2007 | pmid = 17573723 | doi = 10.1111/j.1398-9995.2007.01332.x | s2cid = 23540584 }}</ref> Three other egg white proteins are also identified as allergenic: [[ovalbumin]] (Gal d 2), [[ovotransferrin]] (Gal d 3) and [[lysozyme]] (Gal d 4).<ref name=”Caubet_2011″>{{cite journal | vauthors = Caubet JC, Wang J | title = Current understanding of egg allergy | journal = Pediatric Clinics of North America | volume = 58 | issue = 2 | pages = 427–43, xi | date = April 2011 | pmid = 21453811 | pmc = 3069662 | doi = 10.1016/j.pcl.2011.02.014 }}</ref>

is a [[trypsin inhibitor]] with three [[protein domain]]s of the [[Kazal domain]] [[protein family|family]].<ref name=”Lineweaver_1947″>{{cite journal | vauthors = Lineweaver H, Murray CW | title = Identification of the trypsin inhibitor of egg white with ovomucoid | journal = The Journal of Biological Chemistry | volume = 171 | issue = 2 | pages = 565–581 | date = December 1947 | pmid = 20272096 | doi = 10.1016/S0021-9258(17)41067-2 | doi-access = free }}</ref><ref name=”Rimphanitchayakit_2010″>{{cite journal | vauthors = Rimphanitchayakit V, Tassanakajon A | title = Structure and function of invertebrate Kazal-type serine proteinase inhibitors | journal = Developmental and Comparative Immunology | volume = 34 | issue = 4 | pages = 377–386 | date = April 2010 | pmid = 19995574 | doi = 10.1016/j.dci.2009.12.004 | bibcode = 2010DCImm..34..377R }}</ref> The [[homology (biology)|homolog]]s from [[chicken]]s (”Gallus gallus”) and especially [[turkey (bird)|turkeys]] (”Meleagris gallopavo”) are best characterized. It is not related to the similarly named [[ovomucin]], another egg white protein. Chicken ovomucoid, also known as ”’Gal d 1”’, is a known [[allergen]]. It is the protein most often causing [[egg allergy]]. At least four [[IgE]] [[epitope]]s have been identified.<ref name=”Jarvinen_2007″>{{cite journal | vauthors = Järvinen KM, Beyer K, Vila L, Bardina L, Mishoe M, Sampson HA | title = Specificity of IgE antibodies to sequential epitopes of hen’s egg ovomucoid as a marker for persistence of egg allergy | journal = Allergy | volume = 62 | issue = 7 | pages = 758–765 | date = July 2007 | pmid = 17573723 | doi = 10.1111/j.1398-9995.2007.01332.x | s2cid = 23540584 }}</ref> Three other egg white proteins are also identified as allergenic: [[ovalbumin]] (Gal d 2), [[ovotransferrin]] (Gal d 3) and [[lysozyme]] (Gal d 4).<ref name=”Caubet_2011″>{{cite journal | vauthors = Caubet JC, Wang J | title = Current understanding of egg allergy | journal = Pediatric Clinics of North America | volume = 58 | issue = 2 | pages = 427–43, xi | date = April 2011 | pmid = 21453811 | pmc = 3069662 | doi = 10.1016/j.pcl.2011.02.014 }}</ref>

== Structure ==

== Structure ==

⚫

=== Primary Structure ===

Ovocumoid consists of approximately 186 [[Amino acid|amino acids]] which are composed of three protein domains, each of which contain about 60 amino acids.

=== Secondary Structure ===

Ovomucoid is a glycoprotein with a secondary structure that makes up 46% β-sheet, 10% β-turns, 26% α-helix, and 18% random coils.<ref>{{Cite web |title=Ovomucoid – an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/ovomucoid |access-date=2025-11-24 |website=www.sciencedirect.com}}</ref>

=== Tertiary Structure ===

Each domain is attributed by five carbohydrate side chains on each domain, as well as a total of nine intra-domain [[Disulfide|disulfide bonds]] also known as inter-chain disulfide bonds<ref>{{Cite web |title=Ovomucoid – an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/medicine-and-dentistry/ovomucoid |access-date=2025-11-24 |website=www.sciencedirect.com}}</ref>. Every disulfide bond is formed between two [[cysteine]] amino acids located within the same polypeptide chain. <ref>{{Cite web |title=UniProt |url=https://www.uniprot.org/help/disulfid#:~:text=Example:%20P10846,two%20cysteines%20of%20distinct%20proteins. |access-date=2025-11-24 |website=UniProt |language=en}}</ref>

⚫

As the main allergen in eggs, it contains trypsin inhibitor activity<ref>{{Cite journal |last=Bartnikas |first=Lisa M. |last2=Sheehan |first2=William J. |last3=Tuttle |first3=Katherine L. |last4=Petty |first4=Carter R. |last5=Schneider |first5=Lynda C. |last6=Phipatanakul |first6=Wanda |date=2015 |title=Ovomucoid Specific Immunoglobulin E as a Predictor of Tolerance to Cooked Egg |url=https://journals.sagepub.com/doi/10.2500/ar.2015.6.0135 |journal=Allergy & Rhinology |language=en |volume=6 |issue=3 |doi=10.2500/ar.2015.6.0135 |issn=2152-6575 |pmc=5391491 |pmid=26686214}}</ref>, meaning it can block the enzyme tryptin, a crucial enzyme in that aids in digestion by breaking down proteins.

== Biological Functions ==

== References ==

== References ==

Protein found in egg whites

Ovomucoid is a protein found in egg whites. Ovomucoid’s main source is in various avian species like chickens (Gallus gallus domesticus) and ducks (Anatidae) and makes up approximately 11% of proteins^[2] found in egg whites.

It is a trypsin inhibitor with three protein domains of the Kazal domain family.^[3][4] The homologs from chickens (Gallus gallus) and especially turkeys (Meleagris gallopavo) are best characterized. It is not related to the similarly named ovomucin, another egg white protein. Chicken ovomucoid, also known as Gal d 1, is a known allergen. It is the protein most often causing egg allergy. At least four IgE epitopes have been identified.^[5] Three other egg white proteins are also identified as allergenic: ovalbumin (Gal d 2), ovotransferrin (Gal d 3) and lysozyme (Gal d 4).^[6]

Ovocumoid consists of approximately 186 amino acids which are composed of three protein domains, each of which contain about 60 amino acids.

Ovomucoid is a glycoprotein with a secondary structure that makes up 46% β-sheet, 10% β-turns, 26% α-helix, and 18% random coils.^[7]

Each domain is attributed by five carbohydrate side chains on each domain, as well as a total of nine intra-domain disulfide bonds also known as inter-chain disulfide bonds^[8]. Every disulfide bond is formed between two cysteine amino acids located within the same polypeptide chain. ^[9]

Ovomucoid contains an isoelectric point of approximately 4.1^[10] indicating an overall acidic protein, and containing a molecular weight of 28 kDa ^[11]. In contrast to other protein found in egg whites, Ovomucoid is significantly resistant to heat, making it a thermo-resistant molecule.^[12] As a result, individuals who are allergic to Ovomucoid remain allergic to eggs after cooking, as the protein cannot be denatured through heat.

As the main allergen in eggs, it contains trypsin inhibitor activity^[13], meaning it can block the enzyme tryptin, a crucial enzyme in that aids in digestion by breaking down proteins.