Amino Acids Flashcards
(27 cards)
Glycine
building block for protein
not considered an “essential amino acid” because the body can make it from other chemicals
in protein-rich foods including meat, fish, dairy, and legumes
Alanine
important source of energy for
muscles and the central nervous system
strengthens the immune system
helps in the metabolism of sugars and organic acids
displays a cholesterol-reducing effect in animals
Serine
non-essential amino acid in humans (synthesized by the body)
present and functionally important in many proteins
With an alcohol group, serine is needed for the metabolism of fats, fatty acids, and cell membranes; muscle growth; and a healthy immune system
Phenylalanine
building blocks of proteins in
your body
exists in two forms or arrangements: L-phenylalanine and D-phenylalanine
Cysteine
non-essential sulfur-containing amino acid in humans, related to cystine
important for protein synthesis, detoxification, and diverse metabolic functions
peptide bond
chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other
molecule, releasing a molecule of water (H2O).
This is a dehydration synthesis reaction (also known as a condensation reaction), and usually occurs between amino acids,
dipeptide, tripeptide, polypeptide
two amino acids form
join a third amino acid
This reaction occurs naturally within cells, in ribosomes
Hydrogen bonding
present abundantly in the secondary structure of proteins, and also sparingly in tertiary conformation
secondary structure of a protein
involves interactions (mainly hydrogen bonds) between neighboring polypeptide backbones which contain Nitrogen- Hydrogen bonded pairs and oxygen atoms. Since both N and O are strongly electronegative, the hydrogen atoms bonded to nitrogen in one polypeptide backbone can hydrogen bond to the oxygen atoms in another chain and visa-versa. Though they are relatively weak, these bonds offer substantial stability to secondary protein structure because they repeat many times and work collectively.
tertiary protein structure
interactions are primarily between functional R groups of a polypeptide chain; one such interaction is called a hydrophobic interaction. These interactions occur because of hydrogen bonding between water molecules around the hydrophobe that further reinforces protein conformation.
Solubility
Most of the amino acids are usually soluble in water and insoluble in organic solvents
Melting Point
generally melted at a higher temperature of ten above 2000C
Taste
sweet (Gly, Ala & Val), tasteless (Leu) or Bitter (Arg & Ile)
Optical Properties
due to the presence of asymmetric α-carbon atoms
ZwitterIon And Isoelectric Point
zwitter is derived from the German word which means “hybrid”
hybrid molecule containing positive & negative ionic groups
proton shifts from the carboxyl group to the amino group of the self molecule at normal pH cellular levels
amino acids used as precursors for chemicals
used in various industries, such as pesticides and herbicides
threonine can be used to produce herbicide aztreonam and glycine can be used to produce glyphosate, another herbicide
Chemical reactions of amino acids due to carboxyl group
Decarboxylation
Reaction with Alkalis (Salt formation)
Reaction with Alcohols (Esterification)
Reaction with Amines
Amino Acid Reaction with Ninhydrin Reagent
Decarboxylation
The amino acids will undergo alpha decarboxylation to form the corresponding “amines”. Thus important amines are produced from amino
acids.
● Histidine → Histamine + CO2
● Tyrosine →Tyramine + CO2
● Tryptophan →Tryptamine + CO2
● Lysine →Cadaverine + CO2
● Glutamic acid → Gamma Amino Butyric Acid (GABA) +
CO2
Reaction with Alkalis (Salt formation)
The carboxyl group of amino acids can release an H+ ion with the formation of Carboxylate (COO–) ions. These may be neutralized by cations like Na+ and Ca+2 to form Salts. Thus amino acids react with alkalies to form “Salts”.
Reaction with Alcohols (Esterification)
When the amino acids are reacted with an alcohol to form, “Ester”.
The esters are volatile in contrast to the form of amino acids.
Reaction with Amines
Amino acid reacts with Amines to form “Amides”.
Amino Acid Reaction with Ninhydrin Reagent
used to detect primary and secondary amines
excess of ninhydrin, which is originally yellow in colour, reacts with a free α-amino acid group, a purple coloured dye known as Ruhemann’s purple is formed along with an aldehyde and liberation of CO2 gas(primary amines does not liberate CO2). The presence of Ruhemann’s purple imparts purple colour to the product which forms the basis of the Ninhydrin test in order to detect amino acids.
Ninhydrin
tricyclic 1,2,3-trione
functions as an amino acid reagent
vital organic building block, which exposes latent fingerprints on porous surfaces like paper, cardboard and raw wood
Porphyrins + Heme
Glycine + Succinyl-CoA (animals)
Glutamate (bacteria + plants)
