AMINO ACIDS Usage And Synthesis
Amino Acids is the food additive amino acids may be safely used as nutrients added to foods. the food additive consists of one or more of the following individual amino acids in the free, hydrated, or anhydrous form or as the hydrochloride, sodium, or potassium salts: l-alanine, l-arginine, l-asparagine, l-aspartic acid, l-cysteine, l-cys- tine, l-glutamic acid, l-glutamine, aminoacetic acid (glycine), l-his- tidine, l-isoleucine, l-leucine, l-lysine, dl-methionine (not for infant foods), l-methionine, l-phenylalanine, l-proline, l-serine, l-threo- nine, l-tryptophan, l-tyrosine, or l-valine. the additive(s) is used to significantly improve the biological quality of the total protein in a food containing naturally occurring, primarily intact protein that is considered a significant dietary protein source. the amount of the additive added for nutritive purposes plus the amount naturally present in free and combined (as protein) form should not exceed the levels of amino acids expressed as percent by weight of the total protein of the finished food.
of carboxylic acids in which a hydrogen
atom in an aliphatic acid has been
replaced by an amino group. Thus, from
ethanoic acid, the amino acid 2-
aminoethanoic acid (glycine) is formed. All
are white, crystalline, soluble in water (but
not in alcohol), and with the sole exception
of the simplest member, all are optically active.
In the body the various proteins are assembled
from the necessary amino acids
and it is important therefore that all the
amino acids should be present in sufficient
quantities. In humans, twelve of the twenty
amino acids can be synthesized by the body
itself. Since these are not required in the
diet they are known as nonessential amino
acids. The remaining eight cannot be synthesized
by the body and have to be supplied
in the diet. They are known as
essential amino acids.
The amino acids that occur in proteins all have the –NH2 group and the –COOH group attached to the same carbon atom. They are thus alpha amino acids, the carbon atom being the alpha carbon.
Proteins, which constitute around 50% of the dry weight
of living matter, are essential constituents of all living
cells. These are polymers composed of simple monomers
called a-amino acids, linked by peptide linkages.
Autotrophic organisms, principally green plants, synthesize amino acids. The simplest naturally occurring amino acid is glycine (H2NCH2COOH). About 20 commonly occurring amino acids have been identified as building blocks of most plant and animal proteins.
Amino acids are linked by peptide bonds formed between the carboxyl group of the first amino acid and the amino group of the second amino acid. Many such amino acid molecules join together to form peptide linkages and hence the polypeptide. The sequence of these amino acids in the polypeptide determines the shape and structure of proteins and their properties and biological role.