BIOCHEM LEC_ AMINO ACIDS Flashcards
found at the catalytic (active) site in proteins and enzymes due
to its amine-containing side chain
1.Arginine (Arg)
important role in cell division, the healing of wounds, stimulation
of protein synthesis, immune function, and the release of
hormones.
ARGININE
required for the generation of urea - necessary for the removal
of toxic ammonia
ARGININE
required for the synthesis of creatine → degrades to creatinine
(waste product cleared from the body by the kidney)
ARGININE
basic (alkaline by pH) amino acids due to its imidazole side chain
HISTIDINE
direct precursor of histamine - involved in immune response
HISTIDINE
important source of carbon atoms in the synthesis of purines (a
nitrogen base that make up DNA and RNA)
HISTIDINE
growth and repair body tissues and to maintain the myelin
sheaths - protect nerve cells
HISTIDINE
manufacture of red and white blood cells; helps to protect the
body from heavy metal toxicity
HISTIDINE
stimulates the secretion of the digestive enzyme gastrin
HISTIDINE (HIS)
acts as a catalytic site in certain enzymes
HISTIDINE (HIS)
branched-chain amino acids (like valine and isoleucine
LEUCINE (LEU)
second most common amino acid found in protein besides
glycine
LEUCINE (LEU)
in conjunction with valine and isoleucine, boosts the healing of
muscle, skin, and bones; aids in recovery from surgery; and
lowers blood glucose levels.
LEUCINE (LEU)
necessary for the optimal growth of infants and for nitrogen
balance in adults
LEUCINE (LEU)
has a net positive charge, which makes it one of the three basic
(by charge) amino acids
LYSINE (LYS)
plays a role in the production of antibodies and lowers
triglyceride levels
LYCINE (LYS)
growth and bone development in children
LYSINE (LYS)
maintain a proper nitrogen balance in adults
LYSINE (LYS)
helps in the absorption and conservation of calcium
LYSINE (LYS)
important role in the formation of collagen, a component of
cartilage and connective tissue
LYSINE (LYS)
helps to initiate translation of messenger RNA (mRNA) by being
the first amino acid incorporated into the N-terminal position of
all proteins.
METHIONINE (MET)
source of sulfur - for normal metabolism and growth
METHIONINE (MET)
assists the breakdown of fats, helps to detoxify lead and other
heavy metals, helps diminish muscle weakness, and prevents
brittle hair
METHIONINE (MET)
reacts with adenosine triphosphate (ATP) to contribute to the
synthesis of many important substances, including epinephrine
and choline
METHIONINE (MET)
non-polar amino acid - hydrophobic nature of its benzyl side
chain
PHENYLALANINE (PHE)
promotes alertness and vitality, elevates mood, decreases pain,
aids memory and learning, and is used to treat arthritis and
depression
PHENYLALANINE (PHE)
used by the brain to produce norepinephrine, a neurotransmitter
that transmits signals between nerve cells
PHENYLALANINE (PHE)
uses an active transport channel to cross the blood– brain barrier
and, in large quantities, interferes with the production of
serotonin (a neurotransmitter)
PHENYLALANINE (PHE)
part of the composition of aspartame - common sweetener used
in prepared foods as a sugar replacement
PHENYLALANINE (PHE)
plays a key role in the biosynthesis of other amino acids
PHENYLALANINE (PHE)
alcohol-containing amino acid
THREONINE (THR)
important component in the formation of protein, collagen,
elastin (a connective tissue protein), and tooth enamel
THREONINE (THR)
important in the production of neurotransmitters and health of
the nervous system
THREONINE (THR)
helps maintain proper protein balance in the body and aids liver
function, metabolism, and assimilation
THREONINE (THR)
formed from proteins during digestion by the action of
proteolytic enzyme
TRYPTOPHAN (TRP)
precursor for serotonin and melatonin, a neurohormone and
powerful antioxidant.
THYPTOPHAN (TRP)
natural relaxant; it helps alleviate insomnia by inducing sleep,
soothes anxiety, and reduces depression
THRYPTOPHAN (TRP)
used in the treatment of migraine headaches, aids in weight
control by reducing appetite, and helps control hyperactivity in
children
TRYPTOPHAN (TRP)
branched-chain amino acid that is a constituent of fibrous
protein in the body
VALINE (VAL)
needed for muscle metabolism and coordination, tissue repair,
and maintenance of nitrogen balance
VALINE (VAL)
used by muscle tissue as an energy source
VALINE (VAL)
used in treatments for muscle, mental, and emotional problems;
insomnia; anxiety; and liver and gallbladder disease
VALINE (VAL)
one of the simplest of the amino acids
ALANINE (ALA)
involved in the energy-producing breakdown of glucose.
ALANINE
a product of the breakdown of DNA or the dipeptides, anserine
and carnosine, and the conversion of pyruvate, a pivotal
compound in carbohydrate metabolism
ALANINE
plays a major role in the transfer of nitrogen from peripheral tissue
to the liver
ALANINE
helps in reducing the buildup of toxic substances that are
released into muscle cells when muscle protein is broken down
quickly to meet energy needs
ALANINE
strengthens the immune system through production of
antibodies
ALANINE
first isolated in 1806 from asparagus juice - the first amino acid to
be isolated
ASPARAGINE
the β-amide of aspartic acid synthesized from aspartic acid and
ATP
ASPARAGINE
one of the principal and frequently the most abundant of the
amino acids involved in the transport of nitrogen
ASPARAGINE
main function: converting one amino acid into another via:
i. amination (process by which an amine group is
introduced into an organic molecule
ii. transamination (reaction when an amino acid is
transferred to an α-ketoacid. Asparagine is
ASPARAGINE
required by the nervous system and plays an important role in
the synthesis of ammonia
ASPARAGINE
it is alanine with one of the β-hydrogens replaced by a
carboxylic acid group
ASPARTIC ACID
plays a vital role in metabolism during construction of other
amino acids and metabolites in the citric acid cycle
ASPARTIC ACID
amino acids that are synthesized from aspartic acid are:
▪ asparagine, arginine, lysine, methionine, threonine,
isoleucine, and several nucleotides
ASPARTIC ACID
is also a metabolite in the urea cycle and participates in
gluconeogenesis - generation of glucose from non- sugar
carbon substrates
ASPARTIC ACID
classified as a non-essential amino acid
CYSTEINE
it may be essential for infants, the elderly, and individuals with
certain metabolic diseases or malabsorption syndromes
CYSTEINE
important structural and functional component of many proteins
and enzymes
CYSTEINE
named after cystine (its oxidized dimer)
CYSTEINE
potentially toxic and is catabolized in the gastrointestinal tract
and blood
CYSTEINE
absorbed during digestion as cystine, which is more stable in the
gastrointestinal tract:
o Cystine travels to cells, where it is reduced to two
cysteine molecules upon cell entry
CYSTEINE
used as a constituent in the food, pharmaceutical, and personal
care industries
CYSTEINE
largest applications: production of flavors
CYSTEINE
▪ synthesized from a number of amino acids
▪ when an amino group is added to glutamic acid, it forms the
important amino acid glutamine
▪ one of the two amino acids that have a net negative charge (by
pH → very polar molecule
▪ serves as a neurotransmitter and its dysregulation has been
linked to epileptic seizures
GLUTAMIC ACID
important in the metabolism of sugars and fats and aids
transporting potassium into the spinal fluid.
▪ present in a wide variety of foods and is responsible for one of
the five basic tastes of the human sense of taste (umami)
▪ often used as a food additive and flavor enhancer in the form of
its sodium salt, monosodium glutamate.
GLUTAMIC ACID
most abundant amino acid in the body - involved in more
metabolic processes than any other amino acid
▪ Over 61% of skeletal muscle tissue is glutamine
▪ converted to glucose when more glucose is required for energy
and aids in immune function
▪ assists in maintaining the proper acid/ alkaline balance in the
body, provides fuel for a healthy digestive tract, and is the basis
of the building blocks for the synthesis of RNA and DNA.
GLUTAMINE
useful in the treatment of serious illnesses, injury, trauma, burns,
and cancer treatment–related side effects and in wound
healing for postoperative patients
▪ marketed as a supplement used for muscle growth in
weightlifting and bodybuilding
▪ transports ammonia (toxic metabolic by-product of protein
breakdown) to the liver → converted into less toxic urea →
excreted by the kidneys
GLUTAMINE
▪ simplest amino acid synthesized in the body
▪ the only amino acid that is not optically active - it has no
stereoisomers (any of a group of isomers [compounds with the
same molecular formula but a different structural formula in
which atoms are linked in the same order but differ in their spatial
arrangement)
GLYCINE
▪ essential for the synthesis of nucleic acids, bile acids, proteins,
peptides, purines, ATP, porphyrins, hemoglobin, glutathione,
creatine, bile salts, glucose, glycogen, and other amino acids
▪ liver uses glycine to help in the detoxification of compounds and
to help in the synthesis of bile acids
▪ has a sweet taste and is used as a sweetener/taste enhancer
▪ an inhibitory neurotransmitter in the central nervous system (CNS)
▪ serves as a metal complexing agent, retards muscle
degeneration, improves glycogen storage, and promotes
healing
GLYCINE
precursor of hydroxyproline, which is manufactured into
collagen, tendons, ligaments, and heart muscle by the body
▪ involved in wound healing, plays important roles in molecular
recognition, and is an important component in certain medical
wound dressings that use collagen to stimulate wound healing
▪ helps in the healing of cartilage and in the strengthening of joints,
tendons, and heart muscle, and it works with vitamin C to
promote healthy connective tissues
PROLINE
second amino acid that is also an alcohol because of its methyl
side chain, which contains a hydroxy group
▪ needed for the proper metabolism of fats and fatty acids
▪ important role in the body’s synthetic pathways for pyrimidines,
purines (making it important for DNA and RNA function),
creatine, and porphyrins
▪ highly concentrated in all cell membranes
▪ component of the protective myelin sheaths surrounding nerve
fibers
▪ aids in the production of immunoglobulins and antibodies for the
maintenance of a healthy immune system.
SERINE
▪ metabolically synthesized from the important amino acid
phenylalanine to become the para-hydroxy derivative of
phenylalanine
▪ precursor of the adrenal hormones, epinephrine,
norepinephrine, and dopamine and the thyroid hormones,
including thyroxine
▪ important in overall metabolism, aiding in the functions of the
adrenal, thyroid, and pituitary glands
▪ stimulates metabolism and the nervous system, acts as a mood
elevator, suppresses appetite, and helps reduce body fat,
making it useful in the treatment of chronic fatigue, narcolepsy,
anxiety, depression, low sex drive,
TYROSINE
▪ recognized as the 21st amino acid but, unlike other amino acids
present in proteins, it is not coded for directly in the genetic
code. Selenocysteine is encoded by a UGA codon, which is
normally a stop codon.
▪ named as an amino acid in 2002 and found to be the selenium
analogue of cysteine (selenium atom replaces sulfur
▪ present in several enzymes, such as formate dehydrogenases,
glycine reductases, and some hydrogenases
▪ It has been discovered that HIV-1 encodes a functional
selenoprotein, and patients with HIV infection have been shown
to have a lower-than-average blood plasma selenium level.
SELENOCYSTEINE
▪ 22nd naturally occurring genetically encoded amino acid used
by some Archaea (prokaryotic [lacking a membrane-bound
nucleus] and single- celled microorganisms) in enzymes that are
part of their methane-producing metabolism
▪ A lysine derivative that is encoded by the UAG codon, normally
a stop codon, possibly modified by the presence of a specific down- stream sequence forcing the incorporation of pyrrolysine
instead of terminating translation
PYRROLYSINE
found in connective tissue protein collagen - the extra hydrogen-
bonding opportunities offered by the presence of extra hydroxyl
group on these amino acids is a major factor in stabilising
collagen’s characteristic left-handed helical conformation.
Hydroxyproline and Hydroxylysine
▪ appears in a few proteins such as glutathione peroxidase (the
enzyme that helps glutathione to detoxify harmful organic
peroxides)
▪ resemble cysteine in structure, albeit with selenium atom
replacing sulfur atom in the side chain
▪ appears in a few proteins such as glutathione peroxidase (the
enzyme that helps glutathione to detoxify harmful organic
peroxides)
▪ resemble cysteine in structure, albeit with selenium atom
replacing sulfur atom in the side chain
▪ appears in a few proteins such as glutathione peroxidase (the
enzyme that helps glutathione to detoxify harmful organic
peroxides)
▪ resemble cysteine in structure, albeit with selenium atom
replacing sulfur atom in the side chain
SELENOCYSTEINE
▪ (abbreviated as Orn) is similar to Lysine with an amino group at
the end of its side chain
▪ an important player in the urea cycle
▪ precursor to arginine and to certain polyamides
ORNITHINE
▪ derived from carboxylation of ornithine on the side chain
▪ important in the urea cycle.
CITRULLINE
▪ intermediate in the catabolism of methionine and it is closely
connected to the functioning of the methyl-donor compound,
S-adenosylmethionine
HOMOCYSTEINE
▪ an important neurochemical that inhibits neuronal action by
binding to specific receptors (GABA receptors) both pre- and
post-synaptic
▪ the amino acid glycine and glutamate are also
neurotransmitters with glycine acting like GABA to inhibit
neurotransmission and glutamate acting to excite neuronal
action
Gamma-aminobutyric acid (GABA)
▪ antifibrinolytic agent that acts by inhibiting plasminogen
activators which have fibrinolytic properties
Aminocaproic acid
▪ ACE inhibitor used for the management of essential or
renovascular hypertension, congestive heart failure, left
ventricular dysfunction following myocardial infarction, and
nephropathy
▪ ACE inhibitors dilate arteries and veins and promote sodium and
water excretion advantageous to hypertensive patients
CAPTOPRIL
▪ gamma-aminobutyric acid (GABA) agonist used as a skeletal
muscle relaxant used for the relief of painful and uncomfortable
muscle spasms caused by a variety of conditions
▪ known to be particularly useful in treating muscle spasticity
associated with spinal cord injury
BACLOFEN
▪ Antibiotic substance produced by Streptomyces garyphalus.
▪ broad-spectrum antibiotic used in the treatment of tuberculosis
and certain urinary tract infections (UTI)
Cycloserine
▪ pharmaceutical form is D-penicillamine, as L-penicillamine is
toxic (it inhibits the action of pyridoxine)
▪ A pharmaceutical of the chelator class
▪ It chelates gold, copper, mercury and arsenic
▪ a metabolite of penicillin - employed in the chelation therapy of
Wilson’s disease (excessive deposition of copper in the liver brain
and other tissues) although it has no antibiotic properties
▪ indicated to cystinuria to facilitate excretion of cysteine-
penicillamine complex
Penicillamine
▪ structural analogue of the inhibitory neurotransmitter gamma-
aminobutyric acid (GABA)
▪ anticonvulsant medication used in the management of
peripheral neuropathic pains, postherpetic neuralgia, and
partial-onset seizures
GABAPENTIN
▪ aka Valacyclovir, with a brand name Valtrex:
o antiviral drug that has been used to manage and treat
various herpes infections such as genital herpes for
more than 2 decades
▪ This class of drug forms an important part of hepatitis, HIV, and
cytomegalovirus drug regimens.
Valaciclovir
▪ used as a mucolytic in patients with certain lung conditions and
as an antidote for acetaminophen overdose
▪ exerts mucolytic activity through sulfhydril group, which open up
disulphide bonds in mucoproteins and lowers mucous viscosity of
pulmonary secretions
▪ used in cystic fibrosis, and chronic renal insufficiency, as it can
function as an antioxidant.
Acetylcysteine
▪ used topically to reduce unwanted facial hair growth in women
▪ mechanism of action: irreversible inhibition of ornithine
decarboxylase (ODC) in the skin affecting hair growth
Eflornithine
▪ synthetic T4 hormone used to treat hypothyroidism that can be
used along with surgery and radioiodine therapy to manage
thyrotropin-dependent well-differentiated thyroid cancer
Levothyroxine
