[Biology Class Notes] on Keratin Pdf for EXAM

Keratin is a member of the scleroprotein family of fibrous structural proteins. In vertebrates, keratin is a form of keratin. Scales, horns, fur, feathers, nails, paws, calluses, hooves, and the external layer of the skin are all made of this structural material.

Keratin oil frequently helps to shield epithelial cells from harm and stress. In both water and organic solvents, keratin is highly insoluble. Keratin monomers package into intermediate filaments that are durable and form heavy unmineralized epidermal appendages in birds, reptiles, mammals and amphibians.

Chitin is perhaps the only biological substance that can estimate the hardness of keratinized tissue. The primitive, weaker versions of keratin are present across all vertebrates, whereas the tougher, evolved forms are present only in sauropsids (reptiles and birds). Since keratin is immune to digestion, cats regurgitate hairballs. 

While spider silk is known as keratin, the protein’s development might have developed independently of vertebrate silk production.

Hair Keratin

Hair keratin is a protein that can be found in your skin, hair, and nails. Keratin is also present in the organs and glands of the body. Keratin is a defensive protein that is less likely to be scratched or torn than other forms of cells produced by your body.

Keratin therapy users say that their hair is cleaner and easier to handle as a result of using it. The results differ significantly based on whether your hair is safe, to begin with, how thick your hair is natural, and the keratin therapy you use. Keratin functions by smoothing out the overlapping cells that make up your hair strands. The hair cuticle, which is made up of layers of cells, absorbs the keratin, giving hair a full and shiny appearance. Keratin is often said to make curly hair less frizzy, easy to style, and look straighter.

Examples of Occurrence

  • Keratin filaments, which are proteins that have been keratinized, are abundantly present in keratinocytes throughout the hornified layer of the epidermis. They’re also found in epithelial cells as a whole. Antibodies to keratin 8, keratin 5, and keratin 14 react with mouse thymic epithelial cells, for instance. In a genetic analysis of the thymus, such antibodies have been used as fluorescent markers to differentiate subsets of mouse thymic epithelial cells.

  • Both vertebrates contain the α-keratin. Hair (such as wool), the outer layer of skin, nails, claws, horns, and hooves of mammals, as well as the slime threads of hagfish, are all made up of them.

  • Only sauropsids, which include all living reptiles or birds, have the harder β-Keratin. They’re embedded in reptiles’ scales, nails, and paws, and maybe even some reptile shells (Testudines like turtle, tortoise, and terrapin) and beaks, bird feathers, and claws. Beta sheets are the primary source of these keratins. Beta sheets can also be contained in α-keratins.

Keratin Treatment

Keratin treatment is a hairstyling process that requires straightening and flattening of hair to offer it a smooth, straight, streamlined, and elegant look. It has been used since the 1890s. During the 1950s, smoothing keratin was very common among black males and females of almost all races. 

Chemical relaxers, Brazilian hair straightening, Japanese hair straightening, or roller set/blow dryer styling are all used to achieve this look. Furthermore, certain conditioners, shampoos, and hair gels may help in making the hairs straight for some period of time. In certain Southeast Asian countries, the process is known as “rebonding” (e.g. Indonesia, Malaysia, Singapore, and the Philippines). Flat irons and chemicals can be toxic to hair if used often. Split ends are common as a result of over-straightening. Heat protectant sprays, on the other hand, will help to mitigate the damage.

Protein Structure

Israel Hanukoglu and Elaine Fuchs discovered the first keratin sequences (1982, 1983). Such sequences identified two separate but homologous keratin families, dubbed type I and type II keratins, respectively. Hanukoglu and Fuchs proposed a model wherein keratins and intermediate filament proteins have a central 310 residue domain containing four segments in -helical conformation divided by three short linker segments expected to have been in beta-turn conformation, based on their study of the primary structures of such keratins and some other intermediate filament proteins. The crystal structure of a helical domain of keratins was being determined, confirming his theory.

Keratin (greater molecular weight) in horse liver bile duct cells and oval cells.

Multimerization occurs when fibrous keratin molecules supercoil create a really stable, left-handed superhelical motif, resulting in filaments made up of several copies of the keratin monomer.

Disulfide Bridges: The existence of large quantities of the sulfur-containing amino acid cysteine, necessary for the disulfide bridges which confer enhanced strength and rigidity by constant, thermally stable crosslinking — much like non-protein sulphur bridges stabilise vulcanised rubber — is a unique characteristic of keratins, in relation to intramolecular and intermolecular hydrogen bonds.

Cysteine makes up about 14% of human hair. The volatile sulphur compounds produced are responsible for the pungent odours of burning hair and skin. Keratin oil is insoluble in most solvents but a few, including dissociating or reducing agents, due to massive disulfide bonding.

Filament Formation: Keratins have been classified into ‘hard’ and ‘soft’ types, or ‘cytokeratins’ and ‘other keratins,’ according to a theory. The model has since been shown to be right. This was taken into account in a 2006 nuclear addition to classifying keratins.

Intermediate filaments are keratin filaments. Keratin proteins, like other intermediate filaments, develop filamentous polymers through a sequence of assembly phases that start with dimerization and progress through octamers, tetramers, and, if the current theory is right, unit-length-filaments (ULF) sufficient of annealing end-to-end into longer filaments.

Bio Keratin

Peptides derived from hydrolyzed keratin with a high homology and bio-affinity for the keratin found in the hair, skin, and nails.

Heavy amount of hydrophobic amino acids, that improves moisture retention capability.

Functions:

  • effective safety from environmental threats

  • Enhances and restores the micro-relief of the skin.

  • Excellent hair conditioner and protectant.

  • Strengthens the hair scales’ cohesion.

Cosmetic Use:

  • Creams for skins that aren’t well-protected

  • Treatments for nutrition and restructuring.

  • Treatments for eyelashes with make-up.

  • Shampoos and conditioners for hair that is prone to breakage.

  • Hair items that are ideal for your hair.

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