Eleidin is clear intracellular protein which is present in the

stratum lucidum The stratum lucidum (Latin, 'clear layer') is a thin, clear layer of dead skin cells in the epidermis named for its translucent appearance under a microscope. It is readily visible by light microscopy only in areas of thick skin, which are found ...

of the

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...

. Eleidin is a transformation product of the amino acid complex

keratohyalin Keratohyalin is a protein structure found in cytoplasmic granules of the keratinocytes in the stratum granulosum of the epidermis. Keratohyalin granules (KHG) mainly consist of keratin, profilaggrin, loricrin and trichohyalin proteins which contri ...

, the lifeless matter deposited in the form of minute granules within the protoplasm of living cells. Eleidin is then converted to

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...

in the

stratum corneum The stratum corneum (Latin for 'horny layer') is the outermost layer of the epidermis. The human stratum corneum comprises several levels of flattened corneocytes that are divided into two layers: the ''stratum disjunctum'' and ''stratum compact ...

. Eleidin can be found in the

vermilion border The vermilion border (sometimes spelled vermillion border), also called margin or zone, is the normally sharp demarcation between the lip and the adjacent normal skin. It represents the change in the epidermis from highly keratinized external skin ...

of the lip. The lip is thinly keratinized and has a high concentration of eleidin. The red appearance of the vermillion border is due to several factors, one of which is the transparent nature of eleidin showing the color of the

red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

s beneath.

References

{{protein-stub Human proteins