Keratin 90%

Overview of fibrin produced by animal epithelial cells. The main components of hair, feathers, horns, nails, hooves, silk, etc., have a protective effect on animals. Can be divided into two categories: one is α-keratin, such as hair, horn, nail, hooves and other proteins, the molecule is rich in cystine; The other is beta-keratin, such as silk heart protein, which does not contain cysteine and cysteine, but is high in glycine, alanine and serine. Chemical properties are very stable, disulfide bond content is particularly large Chemicalbook, under general conditions are insoluble in water, salt solution, dilute acid and dilute alkali solution, but soluble in inorganic sulfide solution, leather industry with inorganic sulfide to remove leather hair that use this property. Wool and silk with keratin as the main component are very important textile raw materials. Silk heart protein is keratin, accounting for 70 to 75% of the silk, for the insoluble part of the silk, its outer layer is covered with sericin (globulin) accounted for about 22 to 24%, not filamentous, soluble in hot water.

Keratin is mainly composed of a variety of amino acids through the amide bond, the interaction between the active groups on the side chain causes the keratin peptide chain to bend, forming α-helix or β-folded polypeptide chain structure. Among them, the keratin in human hair and wool is generally α-helical longitudinal side-by-side to form α-keratin, which has good scalability. However, the β-keratin in feathers and scales is formed by the parallel accumulation of β-folded structures, and the structure is close to the fully extended state, so the elongation of β-keratin is relatively small.

In general, disulfide bonds within keratin molecules cross-link within and between peptide chains to form a three-dimensional network structure, which makes natural keratin difficult to dissolve and makes it difficult to extract keratin from hair. Ordinary solvents or mild acids and bases can not dissolve the keratin in the hair fiber, relatively strong acids and bases can dissolve the hair protein, can destroy the intermolecular force and keratin secondary and tertiary structure at the same time to break the peptide chain, the products obtained by Chemicalbook are often proteins with small molecular weight, or even peptides, and the yield is low. In order to produce keratin with higher molecular weight and better solubility, it can only be achieved by selectively opening disulfide bond and destroying hydrogen bond. At present, the methods of extracting keratin are roughly mechanical, chemical and biological methods, among which chemical methods can be divided into acid-base hydrolysis, reduction and oxidation methods. Other methods and chemical methods can often be used in combination with each other.

Keratin is a structural protein of ectodermal cells and widely exists in the tissue structure of organisms. There are great differences in keratin content among different tissues, different individuals and even different species. The keratin content was higher in the epithelial tissues of higher vertebrates. However, the content of keratin in general plants is low. Depending on whether it is fibrotic, keratin can be divided into soft keratin and hard keratin two categories. The contents of sulfo-containing amino acids of soft keratin and hard keratin are different. Soft keratin Chemicalbook protein is found in skin and some other tissues. Fibrotic scleratins, non-nutritive, are widely present in the epidermis of humans and animals and in the inner membrane of eggshells. Extracellular scleratins are the main components of hair, feathers, hooves, shells, claws, horns, scales, etc. They are also important structural proteins of connective tissues and play a role in protecting the body. Intracellular soft keratin is the main component of cell membrane, gray matter, spinal cord, retinal nerve and other tissues.