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Sepiapterin Reductase
Sepiapterin reductase is an enzyme that in humans is encoded by the ''SPR'' gene. Function Sepiapterin reductase (7,8-dihydrobiopterin:NADP+ oxidoreductase; EC 1.1.1.153) catalyzes the NADPH-dependent reduction of various carbonyl substances, including derivatives of pteridines, and belongs to a group of enzymes called aldo-keto reductases. SPR plays an important role in the biosynthesis of tetrahydrobiopterin. Reaction Sepiapterin reductase (SPR) catalyzes the chemical reaction L-erythro-7,8-dihydrobiopterin + NADP+ \rightleftharpoons sepiapterin + NADPH + H+ Thus, the two substrates of this enzyme are L-erythro-7,8-dihydrobiopterin and NADP+, whereas its three products are sepiapterin, NADPH, and a single hydrogen ion (H+). This enzyme belongs to the family of oxidoreductases, to be specific, those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 7,8-dihydrobiopterin:NADP+ oxidoreductase. This enzyme p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), 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, 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 include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NAD+
Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other, nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD and NADH (H for hydrogen), respectively. In cellular metabolism, NAD is involved in redox reactions, carrying electrons from one reaction to another, so it is found in two forms: NAD is an oxidizing agent, accepting electrons from other molecules and becoming reduced; with H+, this reaction forms NADH, which can be used as a reducing agent to donate electrons. These electron transfer reactions are the main function of NAD. It is also used in other cellular processes, most notably as a substrate of enzymes in adding or removing chemical groups to or from proteins, in posttranslational modifications. Because of the importa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypersomnolence
Hypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes (such as seasonal affective disorder) and can cause distress and problems with functioning. In the fifth edition of the ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM-5), hypersomnolence, of which there are several subtypes, appears under sleep-wake disorders. Hypersomnia is a pathological state characterized by a lack of alertness during the waking episodes of the day.American Academy of Sleep Medicine. The international classification of sleep disorders: diagnostic & coding manual (2nd ed). Westchester, IL: American Academy of Sleep Medicine, 2005. It is not to be confused with fatigue, which is a normal physiological state. Daytime sleepiness appears most commonly during situations where little interaction is needed. Since hypersomnia impairs patients' attention levels (wakefulness), quality of life may be impacted as well.Morgent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremor
A tremor is an involuntary, somewhat rhythmic muscle contraction and relaxation involving neural oscillations, oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, face, head, vocal folds, trunk, and legs. Most tremors occur in the hands. In some people, a tremor is a symptom of another neurological disorder. Types Tremor is most commonly classified by clinical features and cause or origin. Some of the better-known forms of tremor, with their symptoms, include the following: * Cerebellar tremor (also known as intention tremor) is a slow, broad tremor of the extremities that occurs at the end of a purposeful movement, such as trying to press a button or touching a finger to the tip of one's nose. In classic cerebellar tremor, a lesion on one side of the brain produces a tremor in that same side of the body that worsens with directed movement. Cerebellar damage can also produce a "win ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oculogyric Crises
Oculogyric crisis (OGC) is a rare sudden, paroxysmal, dystonic reaction that may manifest in response to specific drugs, particularly neuroleptics, or medical conditions, such as movement disorders. This neurological phenomenon is characterized by a sustained dystonic, conjugate, involuntary upward deviation of both eyes lasting seconds to hours. The term ''oculogyric'' is applied in reference to the simultaneous upward movement of both eyes, although the reaction may encompass a variety of additional responses. The reaction is not life-threatening. For clarification, oculogyric seizures, also termed versive seizures, represent one of the manifestations of epilepsy. These seizures exhibit the same upward eye movement observed in OGC but are classified as a specific subtype of epilepsy. Signs and symptoms Initial symptoms include restlessness, agitation, malaise, or a fixed stare. Then comes the more characteristically described extreme and sustained upward deviation of the eyes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dystonia
Dystonia is a neurology, neurological Hyperkinesia, hyperkinetic Movement disorders, movement disorder in which sustained or repetitive muscle contractions occur involuntarily, resulting in twisting and repetitive movements or abnormal fixed postures. The movements may resemble a tremor. Dystonia is often intensified or exacerbated by physical activity, and symptoms may progress into adjacent muscles. The disorder may be Heredity, hereditary or caused by other factors such as birth trauma (physical), birth-related or other Injury, physical trauma, infection, poisoning (e.g., lead poisoning) or reaction to Medication, pharmaceutical drugs, particularly Antipsychotic, neuroleptics, or stress. Treatment must be highly customized to the needs of the individual and may include oral medications, chemodenervation Botulinum toxin, botulinum neurotoxin injections, physical therapy, or other supportive therapies, and surgical procedures such as deep brain stimulation. Classification The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irritability
Irritability is the excitatory ability that living organisms have to respond to changes in their environment. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli. When reflecting human emotion and behavior, it is commonly defined as the tendency to react to stimuli with negative affective states (especially anger) and temper outbursts, which can be aggressive. Distressing or impairing irritability is important from a mental health perspective as a common symptom of concern and predictor of clinical outcomes. Definition Irritability is the excitatory ability that living organisms have to respond to changes in their environment. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli. Irritability can be demonstrated in behavioral responses to both physiological and behavioral stimuli, including environmental, situ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcephaly
Microcephaly (from Neo-Latin ''microcephalia'', from Ancient Greek μικρός ''mikrós'' "small" and κεφαλή ''kephalé'' "head") is a medical condition involving a smaller-than-normal head. Microcephaly may be present at birth or it may develop in the first few years of life. Brain development is often affected; people with this disorder often have an intellectual disability, poor motor function, poor speech, abnormal facial features, seizures and dwarfism. The disorder is caused by a disruption to the genetic processes that form the brain early in pregnancy, though the cause is not identified in most cases. Many genetic syndromes can result in microcephaly, including chromosomal and single-gene conditions, though almost always in combination with other symptoms. Mutations that result solely in microcephaly (primary microcephaly) exist but are less common. External toxins to the embryo, such as alcohol during pregnancy or vertically transmitted infections, can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypersalivation
Hypersalivation or hypersialosis is the excessive production of saliva. It has also been defined as increased amount of saliva in the mouth, which may also be caused by decreased clearance of saliva.Medscape > HypersalivationBy Erica Brownfield. Posted: 05/19/2004 Hypersalivation can contribute to drooling if there is an inability to keep the mouth closed or difficulty in swallowing (dysphagia) the excess saliva, which can lead to excessive spitting. Hypersalivation also often precedes emesis (vomiting), where it accompanies nausea (a feeling of needing to vomit). Causes Excessive production Conditions that can cause saliva overproduction include: *Rabies *Pellagra (niacin or vitamin B3 deficiency) *Gastroesophageal reflux disease, in such cases specifically called a water brash (a loosely defined lay term), and is characterized by a sour fluid or almost tasteless saliva in the mouth *Gastroparesis (main symptoms are nausea, vomiting, and reflux) *Pregnancy * Fluoride therapy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Choreoathetosis
Choreoathetosis is the occurrence of involuntary movements in a combination of chorea (irregular migrating contractions) and athetosis (twisting and writhing). It is caused by many different diseases and agents. It is a symptom of several diseases, including GLUT1 deficiency syndrome, Lesch–Nyhan syndrome, phenylketonuria, and Huntington disease and can be a feature of kernicterus (rapidly increasing unconjugated bilirubin that cross the blood-brain-barrier in infants). Choreoathetosis is also a common presentation of dyskinesia as a side effect of levodopa-carbidopa in the treatment of Parkinson disease. The use of crack cocaine or amphetamines Substituted amphetamines, or simply amphetamines, are a chemical class, class of compounds based upon the amphetamine structure; it includes all derivative (chemistry), derivative compounds which are formed by replacing, or substitution reacti ... can result in conditions nicknamed ''crack dancing'', or ''tweaking'' respectively ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seizures
A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, or consciousness. Symptoms vary widely. Some seizures involve subtle changes, such as brief lapses in attention or awareness (as seen in absence seizures), while others cause generalized convulsions with loss of consciousness ( tonic–clonic seizures). Most seizures last less than two minutes and are followed by a postictal period of confusion, fatigue, or other symptoms. A seizure lasting longer than five minutes is a medical emergency known as status epilepticus. Seizures are classified as provoked, when triggered by a known cause such as fever, head trauma, or metabolic imbalance, or unprovoked, when no immediate trigger is identified. Recurrent unprovoked seizures define the neurological condition epilepsy. Clinical features Seizur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sepiapterin Reductase Deficiency
Sepiapterin reductase deficiency is an inherited pediatric disorder characterized by movement problems, and most commonly displayed as a pattern of involuntary sustained muscle contractions known as dystonia. Symptoms are usually present within the first year of age, but diagnosis is delayed due to physicians lack of awareness and the specialized diagnostic procedures. Individuals with this disorder also have delayed motor skills development including sitting, crawling, and need assistance when walking. Additional symptoms of this disorder include intellectual disability, excessive sleeping, mood swings, and an abnormally small head size. SR deficiency is a very rare condition. The first case was diagnosed in 2001, and since then there have been approximately 30 reported cases. At this time, the condition seems to be treatable, but the lack of overall awareness and the need for a series of atypical procedures used to diagnose this condition pose a dilemma.Lohmann, E., Koroglu, C., Ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
