essential amino acid


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essential amino acid

Etymology: L, essentia, quality
an organic compound not synthesized in the body that is essential for protein synthesis in adults and optimal growth in infants and children. Adults require isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Infants need these amino acids plus arginine and histidine. Cysteine and tyrosine are derived from methionine and phenylalanine, respectively, and are considered semiessential. See also amino acid, nonessential amino acid.

essential amino acid

An amino acid that is required for growth and development but that cannot be produced by the body and must be obtained from food. The essential amino acids are histidine, isoleucine, leucine, lysine, methionine, cysteine, phenylalanine, tyrosine, threonine, tryptophan, and valine. Synonym: indispensable amino acid
See also: amino acid

essential amino acid

an AMINO ACID that must be taken in via the diet, as distinct from nonessential amino acids, which can be synthesized by the organism itself, in a process called TRANSAMINATION, using the essential amino acids as a source. In humans there are ten essential amino acids: ARGININE, TRYPTOPHAN, ISOLEUCINE, METHIONINE, THREONINE, LYSINE, LEUCINE, VALINE, HISTIDINE and PHENYLALANINE.
References in periodicals archive ?
The levels of essential amino acids except cystine and methionine were comparable with that for the FAO reference protein.
Plasma essential amino acid changes in sea bass, Dicentrarchus labrax after feeding diets deficient and supplemented in L-Met.
It was calculated by using the ratio of test protein to the reference protein for each of the eight essential amino acids plus histidine in the equation that follows [11]:
According to the original theory, complete proteins had all of the essential amino acids in the right proportions to be used by the body, while incomplete proteins lacked certain amino acids and did not have them in the right proportions.
The current daily requirements based on MBW for growth plus maintenance for each essential amino acid was derived from the x coordinate value of an intersection of a corresponding straight line from two deficient groups and the horizontal line from the control group.
5g/100g crude lipid, an array of essential amino acids in the right proportion, and high amount of sodium, potassium, calcium and phosphorus [6].
The researchers confirmed that the bacteria had also lost many regulatory genes, making it incapable of turning off the flow of essential amino acids.
In conclusion, quantitative estimation of the amino acid requirement using the broken-line model analysis of plasma free amino acid or ammonia concentrations (post-prandial or absorptive) is an acceptable method for the determination of essential amino acid requirements of fish species.
1999), who observed that pigs fed high lysine:DE ratio diets showed higher than average values of essential amino acid digestibility.
Among non-essential amino acids, alanine, glutamic acid, serine, tyrosine and total non essential amino acid digestibilities were increased linearly (p<0.
Whey's benefits for skeletal muscle go beyond those provided by its essential amino acid content, promoting greater muscle accrual than that which occurs from ingesting the essential amino acids alone.
Klein argues instead that "what [women] need is methionine" - an essential amino acid most abundant in animal proteins.