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Lysyl Oxidase
Lysyl oxidase (LOX), also known as protein-lysine 6-oxidase, is an enzyme that, in humans, is encoded by the ''LOX'' gene. It catalyzes the conversion of lysine molecules into highly reactive aldehydes that form cross-links in extracellular matrix proteins. Its inhibition can cause osteolathyrism, but, at the same time, its upregulation by tumor cells may promote metastasis of the existing tumor, causing it to become malignant and cancerous. Structure In the yeast strain ''Pichia pastoris'', lysyl oxidase constitutes a homodimeric structure. Each monomer consists of an active site that includes a Cu(II) atom coordinated with three histidine residues as well as 2,4,5-trihydroxyphenalanine quinone (TPQ), a crucial cofactor. In humans, the LOX gene is located on chromosome 5 q23.3-31.2. The DNA sequence encodes a polypeptide of 417 amino acids, the first 21 residues of which constitute a signal peptide, with a weight of approximately 32 kDa. The carboxyterminus contains ... [...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 reac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quinone
The quinones are a class of organic compounds that are formally "derived from aromatic compounds uch as benzene or naphthalene">benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with any necessary rearrangement of double bonds, resulting in "a fully Conjugated system, conjugated cyclic diketone, dione structure". The archetypical member of the class is 1,4-benzoquinone or cyclohexadienedione, often called simply "quinone" (thus the name of the class). Other important examples are 1,2-benzoquinone (''ortho''-quinone), 1,4-naphthoquinone and 9,10-anthraquinone. The name is derived from that of quinic acid (with the suffix "-one" indicating a ketone), since it is one of the compounds obtained upon oxidation of quinic acid. Quinic acid, like quinine is obtained from cinchona bark, called quinaquina in the indigenous languages of Peruvian tribes. Properties Quinones are oxidized derivativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emphysema
Emphysema, or pulmonary emphysema, is a lower respiratory tract disease, characterised by air-filled spaces ( pneumatoses) in the lungs, that can vary in size and may be very large. The spaces are caused by the breakdown of the walls of the alveoli and they replace the spongy lung parenchyma. This reduces the total alveolar surface available for gas exchange leading to a reduction in oxygen supply for the blood. Emphysema usually affects the middle aged or older population because it takes time to develop with the effects of tobacco smoking, and other risk factors. Alpha-1 antitrypsin deficiency is a genetic risk factor that may lead to the condition presenting earlier. When associated with significant airflow limitation, emphysema is a major subtype of chronic obstructive pulmonary disease ( COPD), a progressive lung disease characterized by long-term breathing problems and poor airflow. Without COPD, the finding of emphysema on a CT lung scan still confers a higher mortal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Respiratory System
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs; in mammals and reptiles these are called alveoli, and in birds they are known as atria. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occipital Horn Syndrome
Occipital horn syndrome (OHS), formerly considered a variant of Ehlers–Danlos syndrome, is an X-linked recessive mitochondrial and connective tissue disorder. It is caused by a deficiency in the transport of the essential mineral copper, associated with mutations in the ATP7A gene. Only about 2/3 of children with OHS are thought to have genetically inherited the disorder; the other 1/3 do not have the disease in their family history. Since the disorder is X-linked recessive the disease affects more males. This is because they do not have a second X chromosome, unlike females, so essentially are lacking the 'backup' copy with proper function. Females are much more likely to be carriers only. For a female to be affected they must carry two defective X chromosomes, not just one.Horn Syndr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Menkes Disease
Menkes disease (MNK), also known as Menkes syndrome, is an X-linked recessive disorder caused by mutations in genes coding for the copper-transport protein ATP7A, leading to copper deficiency. Characteristic findings include kinky hair, growth failure, and nervous system deterioration. Like all X-linked recessive conditions, Menkes disease is more common in males than in females. The disorder was first described by John Hans Menkes in 1962. Onset occurs during infancy, with incidence of about 1 in 100,000 to 250,000 newborns; affected infants often do not live past the age of three years, though there are rare cases in which less severe symptoms emerge later in childhood. Signs and symptoms Affected infants may be born prematurely. Signs and symptoms appear during infancy, typically after a two- to three-month period of normal or slightly slowed development that is followed by a loss of early developmental skills and subsequent developmental delay. Patients exhibit hypot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aneurysms
An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus (starting point) for clot formation (thrombosis) and embolization. As an aneurysm increases in size, the risk of rupture, which leads to uncontrolled bleeding, increases. Although they may occur in any blood vessel, particularly lethal examples include aneurysms of the Circle of Willis in the brain, aortic aneurysms affecting the thoracic aorta, and abdominal aortic aneurysms. Aneurysms can arise in the heart itself following a heart attack, including both ventricular and atrial septal aneurysms. There are congenital atrial septal aneurysms, a rare heart defect. Etymology The word is from Greek: ἀνεύρυσμα, aneurysma, "dilation", from ἀνευρύνειν, aneurynein, "to dilate". Classification Aneurysms are classified by typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lathyrism
Lathyrism is a condition caused by eating certain legumes of the genus ''Lathyrus''. There are three types of lathyrism: '' neurolathyrism'', '' osteolathyrism'', and '' angiolathyrism'', all of which are incurable, differing in their symptoms and in the body tissues affected. Neurolathyrism is the type associated with the consumption of legumes in the genus ''Lathyrus'' that contain the toxin ODAP. ODAP ingestion results in motorneuron death. The result is paralysis and muscle atrophy of the lower limbs. Osteolathyrism, a different type of lathyrism, affects the connective tissues, not the motorneurons. Osteolathyrism results from the ingestion of '' Lathyrus odoratus'' seeds (sweet peas), and is often referred to as odoratism. It is caused by a different toxin, beta-aminopropionitrile, which affects the linking of the subunits of collagen, a major structural protein found in connective tissue. A third type of lathyrism is angiolathyrism, which is similar to osteolathyrism i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
β-aminopropionitrile
Aminopropionitrile, also known as β-aminopropionitrile (BAPN), is an organic compound with both amine and nitrile functional groups. It is a colourless liquid. The compound occurs naturally and is of interest in the biomedical community. Biochemical and medical occurrence BAPN is the toxic constituent of peas from Lathyrus plants, e.g., lathyrus odoratus. Lathyrism, a disease known for centuries, encompasses 2 distinct entities: a disorder of the nervous system (neurolathyrism) leading to limb paralysis, and a disorder of connective tissue, causing either bone deformity (osteolathyrism) or aortic aneurisms (angiolathyrim). BAPN causes osteolathyrism and angiolathyrism when ingested in large quantities." It can cause osteolathyrism, neurolathyrism, and/or angiolathyrism. It is an antirheumatic agent in veterinary medicine. It has attracted interest as an anticancer agent. Production Aminopropionitrile is prepared by the reaction of ammonia with acrylonitrile.Karsten Eller, Erha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desmosine
Desmosine is an amino acid found uniquely in elastin, a protein found in connective tissue such as skin, lungs, and elastic arteries. Desmosine is a component of elastin and cross links with its isomer, isodesmosine, giving elasticity to the tissue. Detection of desmosine in urine, plasma or sputum samples can be a marker for elastin breakdown due to high elastase activity related to certain diseases. Structure Desmosine and its isomer isodesmosine are both composed of four lysine residues, allowing for bonding to multiple peptide chains. The four lysine groups combine to form a pyridinium nucleus, which can be reduced to neutralize positive charge associated, and increase the hydrophobicity. The four lysines form side chains around the pyridinium nucleus with exposed carboxyl groups. The difference between desmosines and isodesmosines are an exchange of a lysine side chain on carbon 1 with a proton on carbon 5. Desmosine is associated with alanine, bonding with it on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridinoline
Pyridinoline, also known as Hydroxylysylpyridinoline, is a fluorescent cross-linking compound of collagen fibers. Crosslinks in collagen and elastin are derived from lysyl and hydroxylysyl residues, a process catalyzed by lysyl oxidase. Fujimoto and colleagues first described the isolation and characterization of a fluorescent material in bovine Achilles tendon collagen and termed it pyridinoline. It is reported to be present in collagen of bone and cartilage, but is absent in collagen of skin. It is not present in newly synthesized collagen and is formed from aldimine cross-links during maturation of collagen fibers. Pyridinoline and deoxypyridinoline were found to be released into the blood during bone degradation and rapidly excreted in the urine. In a preliminary study, both these compounds were proposed as a marker for metastatic bone tumor in patients with prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastin
Elastin is a protein that in humans is encoded by the ''ELN'' gene. Elastin is a key component of the extracellular matrix in gnathostomes (jawed vertebrates). It is highly elastic and present in connective tissue allowing many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of vertebrates and used in places where mechanical energy is required to be stored. Function The ''ELN'' gene encodes a protein that is one of the two components of elastic fibers. The encoded protein is rich in hydrophobic amino acids such as glycine and proline, which form mobile hydrophobic regions bounded by crosslinks between lysine residues. Multiple transcript variants encoding different isoforms have been found for this gene. Elastin's soluble precursor is tropoelastin. The characterization of disorder is consistent with an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
