Vitellin is a protein found in the

egg yolk Among animals which produce eggs, the yolk (; also known as the vitellus) is the nutrient-bearing portion of the egg whose primary function is to supply food for the development of the embryo. Some types of egg contain no yolk, for example bec ...

. It is a phosphoprotein. Vitellin is a generic name for major of many yolk proteins. Vitellin has been known since the 1900s. The periodic acid-Schiff method and Sudan black B dye was used to help determine that Vitellin is a glycolipoprotein because it stained positive when tested. This protein was found to weigh ~540 kDa, given the weight of each of its 4 major subunits. Vitellin is essential in the fertilization process, and embryonic development in egg-laying organisms. This

phosphoprotein A phosphoprotein is a protein that is posttranslationally modified by the attachment of either a single phosphate group, or a complex molecule such as 5'-phospho-DNA, through a phosphate group. The target amino acid is most often serine, threonin ...

acts as a membrane, 1-3.5μm, that encloses the egg that comprises at least five

glycoprotein Glycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as g ...

s that resemble the

zona pellucida The zona pellucida (plural zonae pellucidae, also egg coat or pellucid zone) is a specialized extracellular matrix that surrounds the plasma membrane of mammalian oocytes. It is a vital constitutive part of the oocyte. The zona pellucida first a ...

evident in mammalian organisms. When the egg is fertilized, it buds off from the gamete surface, which results in the fertilization of the membrane in most

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s, amphibians,

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s, and

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

es. During fertilization, the acrosome of the sperm interacts with the vitelline envelope that has species-specific recognition and binding for the sperm. The vitelline membrane consists of two major layers found below the ovary and the outer layer found in the oviduct. This membrane supports the yolk and separates from the

albumen Egg white is the clear liquid (also called the albumen or the glair/glaire) contained within an egg. In chickens it is formed from the layers of secretions of the anterior section of the hen's oviduct during the passage of the egg. It forms arou ...

, or egg white. The proteins that primarily compose the vitelline membrane are the

lysozyme Lysozyme (EC 3.2.1.17, muramidase, ''N''-acetylmuramide glycanhydrolase; systematic name peptidoglycan ''N''-acetylmuramoylhydrolase) is an antimicrobial enzyme produced by animals that forms part of the innate immune system. It is a glycosid ...

and

ovomucin Ovomucin is a glycoprotein found mainly in egg whites, as well as in the chalaza and vitelline membrane. The protein makes up around 2-4% of the protein content of egg whites; like other members of the mucin protein family A protein family ...

foundational for membrane growth during embryonic development. Aside from structural functions, it is also a barrier that permits the diffusion of water and nutrients, and in chickens especially, it is a barrier against microbial infection. Vitellin comprises a vast fraction of the proteins found in eggs, and due to this, they are easily characterized with biochemical methods in order to elucidate molecular, developments, and physiological regulation studies. Vitellin was studied in honey bees and was found that it contributed to the health of the embryo in the form of immunity in the embryonic stages. This immunity came from two of the four domains of this protein structure. The honey bees, the domain of unknown function 1943 (DUF1943), and the von Willebrand factor (vWF) type D domain were linked to pathogen recognition and increased immunity in the embryonic honey bees.

Allergen

Vitellin is an umbrella term for many vitellin sub proteins and some of these sub proteins are linked with egg allergies.

References

Hagedorn, H. H., and J. G. Kunkel. "Vitellogenin and vitellin in insects." ''Annual review of entomology'' 24.1 (1979): 475-505. https://doi.org/10.1146/annurev.en.24.010179.002355 Zhu, Jiang, Leslie S. Indrasith, and Okitsugu Yamashita. "Characterization of vitellin, egg-specific protein and 30 kDa protein from Bombyx eggs, and their fates during oogenesis and embryogenesis." ''Biochimica et Biophysica Acta (BBA) - General Subjects'' 882.3 (1986): 427-436. https://doi.org/10.1016/0304-4165(86)90267-9 Avian proteins Phosphoproteins {{protein-stub

Allergen

See also

References