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Keratinocyte Transglutaminase
Protein-glutamine gamma-glutamyltransferase K is a transglutaminase enzyme that in humans is encoded by the ''TGM1'' gene. Function Keratinocyte transglutaminase enzymes serve to specifically catalyze the development of the cornified cell envelope, a defining characteristic of epidermal keratinocytes that have undergone the termination of differentiation. The specific cross linkages formed by keratinocyte transglutaminase are between n^ε-(γ-glutamyl)lysine residues which develop into isopeptide protein-protein linkages that adds to the stabilization of the cornified cell envelope. In terminally differentiated stratified squamous epithelia, the cornified cell envelope protein linkages allow for a structurally fortified, yet flexible (15 nm thick) layer to the place of the cell membrane, acting as a highly insoluble barrier. The expression of the enzyme is most highly exhibited along the biological membrane of these fully formed epithelial cells, preventing the cell from underg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transglutaminase
Transglutaminases are enzymes that in nature primarily catalyze the formation of an isopeptide bond between γ-carboxamide groups ( -(C=O)NH2 ) of glutamine residue side chains and the ε-amino groups ( -NH2 ) of lysine residue side chains with subsequent release of ammonia ( NH3 ). Lysine and glutamine residues must be bound to a peptide or a protein so that this cross-linking (between separate molecules) or intramolecular (within the same molecule) reaction can happen. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation (proteolysis). The reaction is :Glutamine, Gln-(C=O)NH2 + Lysine, NH2-Lys → Gln-(C=O)NH-Lys + NH3 Transglutaminases can also join a primary amine ( RNH2 ) to the side chain carboxyamide group of a protein/peptide bound glutamine residue thus forming an isopeptide bond :Gln-(C=O)NH2 + RNH2 → Gln-(C=O)NHR + NH3 These enzymes can also Deamidation, deamidate glutamine residues to glutamic acid residues ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyosis Lamellaris
Lamellar ichthyosis, also known as ichthyosis lamellaris and nonbullous congenital ichthyosis, is a rare inherited skin disorder, affecting around 1 in 600,000 people. Presentation Affected babies are born in a collodion membrane, a shiny, waxy-appearing outer layer to the skin. This is shed 10–14 days after birth, revealing the main symptom of the disease, extensive scaling of the skin caused by hyperkeratosis. With increasing age, the scaling tends to be concentrated around joints in areas such as the groin, the armpits, the inside of the elbow and the neck. The scales often tile the skin and may resemble fish scales. Collodion baby In medicine, the term collodion baby applies to newborns who appear to have an extra layer of skin (known as a ''collodion membrane'') that has a collodion-like quality. It is a descriptive term, not a specific diagnosis or disorder (as such, it is a syndrome). Appearance and treatment at birth The appearance is often described as a shiny fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermatitis Herpetiformis
Dermatitis herpetiformis (DH) is a chronic autoimmune blistering skin condition, characterised by intensely itchy blisters filled with a watery fluid. DH is a cutaneous manifestation of coeliac disease, although the exact causal mechanism is not known. DH is neither related to nor caused by herpes virus; the name means that it is a skin inflammation having an appearance (Latin: '' -formis'') similar to herpes. The age of onset is usually about 15–40, but DH also may affect children and the elderly. Men are slightly more affected than women. Estimates of DH prevalence vary from 1 in 400 to 1 in 10,000. It is most common in patients of northern European and northern Indian ancestry, and is associated with the human leukocyte antigen (HLA) haplotype HLA-DQ2 or HLA-DQ8 along with coeliac disease and gluten sensitivity. Dermatitis herpetiformis was first described by Louis Adolphus Duhring in 1884. A connection between DH and coeliac disease was recognized in 1967. Signs and symp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratinocyte
Keratinocytes are the primary type of Cell (biology), cell found in the epidermis (skin), epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells. Basal cells in the stratum basale, basal layer (''stratum basale'') of the skin are sometimes referred to as basal keratinocytes. Keratinocytes form a barrier against environmental damage by heat, UV radiation, Dehydration, water loss, pathogenic bacteria, fungi, parasites, and viruses. A number of structural proteins, enzymes, lipids, and antimicrobial peptides contribute to maintain the important barrier function of the skin. Keratinocytes differentiate from epidermal stem cells in the lower part of the epidermis and migrate towards the surface, finally becoming corneocytes and eventually be shed off, which happens every 40 to 56 days in humans. Function The primary function of keratinocytes is the formation of a barrier against environmental damage by heat, UV radiation, Dehydration, wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
