Amino acid (redirected from Aromatic amino-acid)

amino acid /ami·no ac·id/ (ah-me´no) one of a class of organic compounds containing the amino (NH2) and the carboxyl (COOH) groups; they occur naturally in plant and animal tissue and form the chief constituents of protein.

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branched-chain amino acids  leucine, isoleucine, and valine.

essential amino acids  the nine a-amino acids that cannot be synthesized by humans but must be obtained from the diet.

nonessential amino acids  the eleven a-amino acids that can be synthesized by humans and are not specifically required in the diet.

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amino acid

n. Abbr. AA

Any of various organic acids containing both an amino group and a carboxyl group, especially any of the 20 or more compounds that link together to form proteins.

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Amino acid

Amino acids are small molecules that are used as building blocks for all proteins. Some amino acids are also used in the body for the manufacture of hormones. There are about 20 nutritionally important amino acids, including glutamic acid, glycine, methionine, lysine, tryptophan, serine, and glycine.

Mentioned in: Amino Acid Disorders Screening, Cystinuria, Homocysteine, Phenylketonuria, Sickle Cell Disease, Stress Reduction, sub> Deficiency

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amino acid,

n an organic acid in which one of the CH hydrogen atoms has been replaced by NH₂. Amino acids are the building blocks of proteins.

amino acid, essential,

n the group of amino acids that cannot be synthesized by the organism but are required by the organism. They must be supplied by the diet. Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine are essential for adults; these eight plus arginine and histidine are considered essential for infants and children.

amino acid, glucogenic

n the group of amino acids that produce enzymes that may be converted to glucose if necessary.

amino acid, ketogenic

n an amino acid that produces ketone bodies following chemical alteration of its carbon skeleton.

amino acid, nonessential,

n the group of amino acids that can be synthesized by the organism and are not required in the diet.

amino acid pool,

n an accumulation of amino acids in the liver and blood that adjusts to meet the body's need for protein and amino acids.

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amino acid

any one of a class of organic compounds containing the amino (NH₂) and the carboxyl (COOH) group, occurring naturally in plant and animal tissues and forming the chief constituents of protein.

In certain inherited or acquired disorders of metabolism, specific amino acids accumulate in the blood (aminoacidemia) or are excreted in excess in the urine (aminoaciduria). Urinary amino acid levels are increased in liver disease, muscular dystrophies, phenylketonuria (PKU), lead poisoning and folic acid deficiency.

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acidic amino acid a's

those containing carboxylic acids in their side chains, e.g. aspartate and glutamate.

basic amino acid a's

amino acids containing side chains that accept protons at physiological pH, e.g. lysine, arginine, and histidine.

branched-chain amino acid a's

methyl branched amino acids.

amino acid dehydratase

an enzyme which contributes significantly to the total production of ammonia in the body.

essential amino acid a's

the amino acids which animals must ingest with their diets and which vary between species and physiological status. The commonly accepted list of essential amino acids includes arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Birds also require glycine and cats require taurine in their diets.

free amino acid a's

amino acids free in the blood, providing an available source for all tissues for catabolism.

glucogenic amino acid

an amino acid which yields either pyruvate or oxaloacetate and glucose synthesis can occur.

ketogenic amino acid

an amino acid whose carbon skeleton yields ketone bodies; leucine is an example.

amino acid nutritional deficiency

the effects may be the same as a deficiency of total protein, reduced growth and production, reduced food intake, loss of body weight, but deficiencies of individual amino acids may have specific effects, e.g. taurine in cats. See also methionine, lysine, arginine.

amino acid poisoning

methionine has caused growth retardation and cervical paralysis in turkey poults.

amino acid ratio

a decreased ratio of branched chain to aromatic amino acids in plasma can be used to detect chronic liver disease or portacaval shunts in dogs.

amino acid sequencer

automatic machine for determining the amino acid sequence of a protein.

sulfur amino acid a's

essential amino acids containing sulfur, cysteine, cystine and methionine.

amino acid transamidation

see transamidation.

amino acid transamination

see transamination.

urinary amino acid a's

analysis may be used to detect inherited disorders of metabolism, such as cystinuria, tyrosinemia and citrullinemia.