Definition
Widely distributed in nature as one of the principal protein amino acids. Dietary supplement Branched chain amino acids (BCAA) are essential amino acids whose carbon structure is marked by a branch point. These three amino acids are critical to human life and are particularly involved in stress, energy and muscle metabolism. BCAA supplementation as therapy, both oral and intravenous, in human health and disease holds great promise. 'BCAA' denotes valine, isoleucine and leucine which are branched chain essential amino acids. Despite their structural similarities, the branched amino acids have different metabolic routes, with valine going solely to carbohydrates, leucine solely to fats and isoleucine to both. The different metabolism accounts for different requirements for these essential amino acids in humans: 12 mg/kg, 14 mg/kg and 16 mg/kg of valine, leucine and isoleucine respectively. Furthermore, these amino acids have different deficiency symptoms. Valine deficiency is marked by neurological defects in the brain, while isoleucine deficiency is marked by muscle tremors.; Many types of inborn errors of BCAA metabolism exist, and are marked by various abnormalities. The most common form is the maple syrup urine disease, marked by a characteristic urinary odor. Other abnormalities are associated with a wide range of symptoms, such as mental retardation, ataxia, hypoglycemia, spinal muscle atrophy, rash, vomiting and excessive muscle movement. Most forms of BCAA metabolism errors are corrected by dietary restriction of BCAA and at least one form is correctable by supplementation with 10 mg of biotin daily. BCAA are decreased in patients with liver disease, such as hepatitis, hepatic coma, cirrhosis, extrahepatic biliary atresia or portacaval shunt; L-valine is a branched-chain essential amino acid (BCAA) that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway. Valine is one of three branched-chain amino acids (the others are leucine and isoleucine) that enhance energy, increase endurance, and aid in muscle tissue recovery and repair. This group also lowers elevated blood sugar levels and increases growth hormone production. Supplemental valine should always be combined with isoleucine and leucine at a respective milligram ratio of 2:1:2. It is an essential amino acid found in proteins; Valine (abbreviated as Val or V) is an ?-amino acid with the chemical formula HO2CCH(NH2)CH(CH3)2. L-Valine is one of 20 proteinogenic amino acids. Its codons are GUU, GUC, GUA, and GUG. This essential amino acid is classified as nonpolar. Along with leucine and isoleucine, valine is a branched-chain amino acid. It is named after the plant valerian. In sickle-cell disease, valine substitutes for the hydrophilic amino acid glutamic acid in hemoglobin. Because valine is hydrophobic, the hemoglobin does not fold correctly.; Valine is an essential amino acid, hence it must be ingested, usually as a component of proteins. And will flow bood engorged pumps to the penile region. It is synthesized in plants via several steps starting from pyruvic acid. The initial part of the pathway also leads to leucine. The intermediate ?-ketovalerate undergoes reductive amination with glutamate. Enzymes involved in this biosynthesis include:; aromatic amino acids (AAA)-tyrosine, tryptophan and phenylalanine, as well as methionine-are increased in these conditions. Valine in particular, has been established as a useful supplemental therapy to the ailing liver. All the BCAA probably compete with AAA for absorption into the brain. Supplemental BCAA with vitamin B6 and zinc help normalize the BCAA:AAA ratio. (http://www.dcnutrition.com)
Description
Valaciclovir (INN) or valacyclovir (USAN) is an antiviral drug used in the management of herpes simplex and herpes zoster (shingles). It is a prodrug, being converted in vivo to aciclovir. It is marketed by GlaxoSmithKline under the trade name Valtrex or Zelitrex. [Wikipedia]
L-Valine Health Effects
General Information
- Metabolism: Valaciclovir is rapidly and almost entirely (~99%) converted to the active compound, acyclovir, and L-valine by first-pass intestinal and hepatic metabolism by enzymatic hydrolysis. Neither valaciclovir nor acyclovir is metabolized by cytochrome P450 enzymes. Acyclovir is converted to a small extent to inactive metabolites by aldehyde oxidase and by alcohol and aldehyde dehydrogenase. Plasma concentrations of unconverted valacyclovir are low and transient, generally becoming non-quantifiable by 3 hours after administration. Peak plasma valacyclovir concentrations are generally less than 0.5 mcg/mL at all doses. After single-dose administration of 1 gram of VALTREX, average plasma valacyclovir concentrations observed were 0.5, 0.4, and 0.8 mcg/mL in patients with hepatic dysfunction, renal insufficiency, and in healthy volunteers who received concomitant cimetidine and probenecid, respectively. Route of Elimination: Acyclovir accounted for 89% of the radioactivity excreted in the urine. Half Life: 2.5-3.3 hours
- Uses/Sources: For the treatment or suppression of cold sores (herpes labialis), herpes zoster (shingles), genital herpes in immunocompetent individuals, and recurrent genital herpes in HIV-infected individuals. Cold Sores (Herpes Labialis): VALTREX is indicated for treatment of cold sores (herpes labialis). The efficacy of VALTREX initiated after the development of clinical signs of a cold sore (e.g., papule, vesicle, or ulcer) has not been established. Genital Herpes: Initial Episode: VALTREX is indicated for treatment of the initial episode of genital herpes in immunocompetent adults. The efficacy of treatment with VALTREX when initiated more than 72 hours after the onset of signs and symptoms has not been established.
- Health Effects: General: Facial edema, hypertension, tachycardia. Allergic:Acute hypersensitivity reactions including anaphylaxis, angioedema, dyspnea, pruritus, rash, and urticaria. CNS Symptoms: Aggressive behavior; agitation; ataxia; coma; confusion; decreased consciousness; dysarthria; encephalopathy; mania; and psychosis, including auditory and visual hallucinations, seizures, tremors. Eye: Visual abnormalities. Gastrointestinal: Diarrhea. Hepatobiliary Tract and Pancreas: Liver enzyme abnormalities, hepatitis. Renal: Renal failure, renal pain (may be associated with renal failure). Hematologic: Thrombocytopenia, aplastic anemia, leukocytoclastic vasculitis, TTP/HUS. Skin: Erythema multiforme, rashes including photosensitivity, alopecia.
- Symptoms: Adverse effects of overexposure might include headache and nausea.
- Treatment: In the event of acute renal failure and anuria, the patient may benefit from hemodialysis until renal function is restored. (L1712)
- Route of Exposure: After oral administration, valaciclovir hydrochloride is rapidly absorbed from the gastrointestinal tract. The absolute bioavailability of acyclovir after administration of valaciclovir is 54.5% ± 9.1%.
Mechanism of Action
| Target Name | Mechanism of Action | References |
|---|---|---|
|
Propionyl-CoA carboxylase beta chain, mitochondrial Branched-chain-amino-acid aminotransferase, cytosolic Valine--tRNA ligase |
17554170 17095543 15710393 17077963 12409268 15667998 17016423 17139284 |