Keratin isFibre structureOne of the protein families, it is the main protein that constitutes the outer layer of hair, horn, claw and human skin.Keratin can protect epithelial cells from damage or stress.Keratin monomer forms bundles to form intermediate protein (IP).[1]
Chinese name
Keratin[4]
Foreign name
KERATIN，ANIMAL KERATIN
CAS
169799-44-4[4]
Features
Insoluble or slightly soluble in water, dilute acid or dilute alkali
Keratin peptide chain is a multi domain peptide chain, which is divided into highly reserved rod like intermediate region and terminal peptide region.The peptide chain of the rod like domain has a periodic sequence structure of 8 peptide repeats.All intermediate filament eggs have similar peptide chain structure.Keratin peptide chain is typicalαSpiral.The heterologous complex helix formed by the combination of acidic and basic keratin peptide chains is the characteristic conformational form of keratin.
More than 20 kinds of keratin peptide chains have been found. Hair keratin and epidermal keratin are composed of different keratin skin chains.Keratin contains highCysteineThe cross-linking of cysteine is the main cross-linking structure of keratin, and the physical and chemical properties of keratin are mainly related to this cross-linking structure.[2]
Nature and structure
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Keratin structural formula
Insoluble in water, salt solution, dilute acid or dilute alkali.Keratin comes fromEctodermThe differentiated cells are those insidestructural proteinone of.Therefore, keratin exists in hair, hairscale, feather, nailHoof, angle, clawbeak, silk and othersEpidermal structureMiddle, feathers, hair, claws, beaks, hooves, horns andCerebral gray matter、spinal cordandRetinal nerveProtein.
Because keratin contains moreCystine, soDisulfide bondThe content is particularly high, especially in proteinPeptide chainMedium riseCross-linking, so keratinchemical propertyEspecially stable, with high mechanical strength.They are not easy to dissolve and digest, and contain more cystine (14-15%) and more nitrogen (21-24.5%).Crushed feathers andPig hair, heated for one hour at 15-20 pounds of steam pressureDigestibilityIt can be increased to 70-80%, and cystine content can be reduced by 5-6%.[2]
distribution
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Keratin is the structural protein of ectodermal cells, including hair, nails, feathers, etc.Keratin is a hard protein that cannot be directly absorbed and utilized by livestock and poultry. It mainly exists in animal hair, feathers and hooves. It is very rich in resources. It must be treated with high temperature, high pressure, acid, alkali or enzyme to becomesmall peptideOr free amino acids can be used by livestock and poultry.Feather is mainly composed of keratin. The protein content and essential amino acid content are extremely high. The amino acid composition is relatively stable. It is recognized as a potential high-quality protein source with high nutritional value and stable quality.[1]
Application of Keratin
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Feed and food industry
Feather keratin can be used as high quality feed protein.Keratin can also be used to produce amino acid trace element chelating agent, which can react with trace metal ions necessary for the growth of livestock and poultry to produce ring shapedCoordination compoundAnd improve the utilization rate of trace elements.Feather keratin also contains rich glutamic acid, aspartic acid and other delicious amino acids, which can be used to produce newfood additivesIt is applied to food processing industry.[1]
pharmacy
It is found that some skin diseases are caused by the penetration of keratinase produced by fungal substances into the skin, which can be used to research and develop drugs for fungal skin diseases.Compound angleProtein amino acidThe solution can be directly injected into the human body to supplement nutrition and replace some human plasma.Cystine in keratin can protect the liver, effectively prevent fatty liver, cirrhosis and other liver diseases, and also has significant effects in the treatment of cystitis, alopecia, toxic diseases, etc.[1]
Fertilizers, Pesticides and Environmental Protection
The treated feather meal contains up to 5% of nitrogen source, which can be used to produce liquid amino acid compound fertilizer as a substitute for animal feces and become a cheaper fertilizer.
KeratinhydrolysisThe prepared amino acids and their derivatives, metal complexes have dual effects of sterilization, disease prevention and growth stimulation on crops, and can be used as fungicides, pesticides, herbicides and plantsGrowth promoter。Hydrolyzed feather preparationCompound amino acidAnd react with calcium carbonate to prepare a compound of calcium amino acid, which can be hydrolyzedOrganophosphorus pesticideThe phosphate ester bond in reduces pesticide residues in crops.[1]
Tanning industry
The softness and elongation of leather can be improved obviously by filling cattle hide upper leather with feather hydrolysate, but the tensile strength, tear strength and dye absorption of leather are not affected obviously.After proper alkali degradation treatment, the protein mixture obtained from feather can be used as the filling material of shoe upper leather and garment leather, improving the dyeing performance of leather and making leather have better elasticity.In addition, feather protein can also be used as a retanning agent for chrome leather.[1]
Cosmetics
Keratin can be used in cosmetics.Keratin has high resistance physical and chemical properties and special biological functions, and plays an important role in maintaining normal physiological functions of epidermis.Keratin is used in beauty care products to help active factors pass throughSkin barrierIt has a good prospect in the field of skin beauty to remove redundant cutin, achieve deep skin care and hair removal.[3]
